National Measurement Guidelines 2026

The Guidelines revolve around a small set of technical and definitional concepts. These are stated directly in the text and determine the permitted operations on Australian legal units of measurement.

• Australian legal units of measurement and physical quantities: The Guidelines apply only to Australian legal units of measurement formed for the physical quantities that are prescribed in the Regulations (s 7). That ties the permissible universe of units to what the Regulations list; the Guidelines do not themselves prescribe all physical quantities.

• Combination according to mathematical relations: Derived units are to be formed by combining Australian legal units in accordance with the mathematical relations that connect the corresponding physical quantities (s 8(1)). The Guidelines therefore defer to the scientific/mathematical relationships among quantities when allowing formation of derived units (s 8(2) gives the example Pa = N/m2).

• SI Prefix: Defined by reference to Schedule 3 of the Regulations (s 5). The core rule is that a decimal multiple or submultiple of a unit must be formed by using a single SI Prefix (s 9(1)). This single-prefix rule prevents chaining prefixes (for example, s 9(1) says 1 nm or 1 x 10-9 m is acceptable but not 1 mµm).

• Special treatment of kilogram: The kilogram is explicitly excluded from the single-prefix rule in s 9(2); instead, the Guidelines instruct that decimal multiples or submultiples of kilogram must be formed by attaching a prefix to gram (note to s 10(2) reinforces that kilogram historically already contains a prefix). The Guidelines therefore create a directed practice for handling the base unit kilogram.

• Units excluded from prefixing: s 10(1) lists units that must not be combined with SI prefixes. That list includes a mix of SI base units (kilogram), time units (minute, hour, day), angle units (degree, minute, second of arc, radian, steradian), non-SI units in common use (inch, foot, ounce, hectare), and other specified units such as decibel and degree Celsius. The list also includes compound units such as foot/minute.

• Tonne prefix limitation: Tonne may only be combined with SI prefixes that form multiples (s 11). The text gives the example kilotonne but explicitly disallows millitonne, so prefixes that would create submultiples are not permitted on tonne.

• Expression rules: Section 12 contains multiple rules on presentation: names and symbols must not be mixed in a single expression (12(1)); adjectives or signs cannot be added to a unit name or symbol (12(2)); SI prefix symbols must be contiguous with the unit symbol (12(4)); only one SI prefix may be used on a derived unit (12(11)); and the product symbol rules (12(12)-(14)) specify acceptable separators (dot, full stop, or space, depending on ambiguity and whether the unit symbol coincides with an SI prefix), with examples (for instance, m·K/W for metre kelvin per watt). Section 12 also covers fraction expressions, the prohibition on repeated oblique slashes without parentheses (12(16)-(17)), and spacing after numerical values (12(18)), including specific exceptions for geographic coordinates and plane angles (12(19)-(20)).

• Interaction with Regulations and the Act: The Guidelines repeatedly reference the Regulations (s 5, s 7, s 9(3), and in notes), placing the Guidelines as a subordinate instrument that operates in the regulatory framework established by the National Measurement Act 1960 and the National Measurement Regulations 1999 (s 3 and s 5).

These core concepts define the permitted algebra of unit formation, the allowed or disallowed prefixing operations, and the required visual and textual presentation of units and their numerical values. The Guidelines are technical and prescriptive in form.

The instrument’s text specifies its subject-matter rather than a list of persons, but its commands apply to anyone who uses Australian legal units of measurement in a way that must comply with the National Measurement legislative scheme.

• Primary legal relationship: The Guidelines are made under section 7B of the National Measurement Act 1960 (s 3). They are subordinate instruments that operate within the Act/Regulations regime. Therefore, the immediate legal addressees are those persons whose use of units falls within the ambit of that Act and its Regulations. The Guidelines themselves say they "govern the way in which Australian legal units of measurement may be combined" (s 6). That wording indicates the Guidelines apply to the formation and expression of Australian legal units wherever Australian legal units are required or mandated.

• Regulated activities: The Guidelines apply to the formation of Australian legal units of measurement for the physical quantities prescribed under the Regulations (s 7). Anyone required to express measurements of those prescribed physical quantities , for example, manufacturers labelling products, importers, testing and calibration laboratories, published standards, and government or industry measurement reports , will be affected to the extent the Act and Regulations impose legal requirements to use Australian legal units. The Guidelines do not themselves list regulated industries but tie their substantive scope to the Regulations.

• Users of derived units and prefixes: Entities that create or use derived units, or who attach SI prefixes to units, are directly affected. The Guidelines set rules on combining units (s 8), on prefix usage (s 9-11), and on expression and formatting (s 12). That covers designers of technical documentation, manufacturers’ labels, instrument displays, standards writers, software that formats measurement values, and legal drafting that includes units.

• Entities handling particular units: The list in s 10(1) designates specific units that must not be combined with prefixes. Actors who use any unit in that list (kilogram, minute, hour, day, decibel, inch, foot, hectare, ounce, foot/minute, degree, minute, second of arc, radian, steradian, degree Celsius) must ensure they do not attach SI prefixes to those units. Operators who use tonne must adhere to s 11 and only use prefixes that make multiples.

• Those preparing legal or public-facing material: The expression rules in s 12 are prescriptive about how to display numerical values and units (for example, spacing, prefix placement, product symbol usage, and prohibition on mixing names and symbols). Anyone producing labelling, public data, technical specifications, instrumentation readouts, or statutory instruments that include measurements will need to comply with these formatting rules where Australian legal units are required.

• Relationship to regulators and metrology authorities: The Guidelines are made by the Chief Metrologist at the National Measurement Institute (front matter). As such, the National Measurement Institute’s technical and compliance functions are implicated, because the Guidelines define the correct forms that measurement expressions must take under the legislative framework. The exact enforcement responsibilities are not set out in the Guidelines text; enforcement would arise under the Act and Regulations.

In short, the population affected is all users who are required by the National Measurement Act and Regulations to express measurements using Australian legal units for the physical quantities the Regulations prescribe, and in particular those preparing labels, technical documentation, instrument readouts and statutory text involving such units.

The Guidelines impose prescriptive duties about unit formation and expression rather than confer explicit rights. The duties and directional commands are set out in specific provisions; rights are implicit in the legal certainty the Guidelines aim to provide.

Key duties (expressed in the instrument):

• Duty to form units only for prescribed physical quantities: Australian legal units "may be formed only for the physical quantities as prescribed under the Regulations" (s 7). This is a limiting rule that constrains unit formation to the Regulations’ list.

• Duty to combine units according to mathematical relations: A derived Australian legal unit "may be formed by combining Australian legal units of measurement according to the mathematical relations linking the corresponding physical quantities" (s 8(1)). This requires that any derived unit must reflect the underlying physics or mathematics of the quantities combined. Section 8(2) permits representing the resulting unit by a name or symbol formed from derived units.

• Duty to use a single SI Prefix for decimal multiples/submultiples: "A decimal multiple, or submultiple, of an Australian legal unit of measurement must be formed by using a single SI Prefix" (s 9(1)). That is a strict formatting/formation duty. There is an explicit example disallowing compound prefixes (1 mµm).

• Duty to follow special rules for kilogram: Subsection 9(1) does not apply to kilogram (s 9(2)); instead, a decimal multiple or submultiple of kilogram must be formed by attaching a prefix to gram (s 10(2) note). This is a directed duty that changes the mechanically correct way to express multiples of kilogram.

• Duty not to prefix certain listed units: Section 10(1) provides a list of units that "must not be combined with SI prefixes". The duty to refrain from prefixing applies to every unit on that list, including minute, hour, day, degree, decibel, inch, hectare, etc.

• Duty regarding tonne: Tonne "may be combined only with an SI Prefix that gives a decimal multiple of tonne" (s 11). That prohibits submultiple forms like millitonne.

• Duties on expression and formatting: Section 12 contains multiple duties about presentation:

  • Names and symbols must not be used together in the same expression (12(1)).
  • No adjective or sign may be added to a unit name or symbol (12(2)).
  • SI prefix symbols must be placed immediately before the unit symbol without intermediate space (12(4)).
  • Only a single SI Prefix may be used to form a multiple of a derived unit (12(11)).
  • The product symbol must be used only with symbols (12(14)).
  • Use of oblique stroke, negative exponent or horizontal line for division, and constraints on repeating oblique strokes without parentheses (12(15)-(17)).
  • A space must be left after the numerical value and before the unit (12(18)), with specified exceptions (12(19)-(20)).

Rights and implied benefits:

• Legal certainty in unit presentation: By prescribing exact methods of combining and presenting units, the Guidelines create a uniform technical standard for unit expression under the Act/Regulations framework. This is an implicit right to a clear, authoritative technical rule set for regulated parties.

• Predictability for compliance design: The single-prefix rule, the list of forbidden prefixing, the kilo/gram rule, and the expression rules allow businesses and regulators to design templates, labels, and automated formatting that should meet the Guidelines’ requirements.

• Delegated technical clarification: The Guidelines operate as a delegated instrument under s 7B of the Act (s 3). For persons required to use Australian legal units, these Guidelines clarify technical matters that would otherwise be uncertain or variable.

Gaps and delegations:

• The Guidelines repeatedly tether their operation to the Regulations: for permitted physical quantities (s 7) and for SI Prefix definitions (s 5). Therefore the duties under the Guidelines are dependent on the content of the Regulations, which the Guidelines do not reproduce. That places an implicit duty on regulated parties to consult the Regulations and the referenced Schedule 3 for a complete compliance picture.

• The Guidelines do not specify enforcement powers or penalties within their text. Any rights to enforcement or remedies for non-compliance must be sourced in the Act or Regulations; the Guidelines are technical requirements that feed into the broader legal framework.

In summary, the instrument creates prescriptive duties about how Australian legal units are formed and written, specifies where prefixes are disallowed or restricted, and mandates formatting conventions. Rights are primarily the legal clarity provided to those who must present measurements under the National Measurement legislative scheme.

The Guidelines, as transcribed, do not contain any provisions that establish offences, penalties, sanctions or detail enforcement mechanisms. The text is a set of technical rules and definitions and does not itself:

• Create criminal or civil penalties;
• Specify administrative sanctions or infringement regimes; or
• Assign inspection, seizure or compliance powers.

Authority and referral: The instrument is made under section 7B of the National Measurement Act 1960 (s 3). That indicates the Guidelines are a subordinate legislative instrument within the Act’s framework. Any legal consequences for failing to follow the Guidelines therefore arise, if at all, from the National Measurement Act 1960 and the National Measurement Regulations 1999, which the Guidelines reference (see s 3 and s 5). The Guidelines refer to the Regulations for key definitions (SI Prefix, Schedule 3 of the Regulations) and for the list of physical quantities (s 7), implying that enforcement and the legal status of non-compliance will be understood in the context of those higher-level instruments.

Practical implications for compliance and enforcement:

• Regulators and compliance officers should treat the Guidelines as mandatory technical specifications that will inform any statutory compliance obligations under the Act/Regulations. The Guidelines set the form that is required for unit combination and expression within that statutory framework, but the instrument itself does not articulate enforcement tools.

• Where enforcement or penalty provisions are relevant, they must be located in the National Measurement Act 1960 or the National Measurement Regulations 1999. The Guidelines make no attempt to restate, duplicate or modify enforcement provisions; they simply establish technical standards.

• Because the Guidelines repeal the earlier 2016 Guidelines in full (Schedule 1,Repeals), any enforcement practice or compliance expectations that previously referenced the 2016 Guidelines will need to be aligned with the 2026 text. The instrument does not state how existing compliance notices, directions or approvals relying on the 2016 Guidelines should be treated; the only textual change is the express repeal (Schedule 1).

For legal practice: when advising clients about potential penalties or enforcement risk for unit expression or labelling, the adviser must consult the Act and Regulations for specific offence provisions, and treat these Guidelines as the definitive technical rules that will be applied in any assessment of whether an expression of a unit meets the legal standard.

The Guidelines are explicitly nested within the National Measurement legislative framework and reference the Regulations for key definitions and lists. The instrument’s own text sets out the following interactions with other legal instruments:

• Made under the Act: The Guidelines are made under section 7B of the National Measurement Act 1960 (s 3). That places the Guidelines as subordinate to the Act; they derive their legal force from the power granted under that statutory provision.

• Reliance on the Regulations: The Guidelines define SI Prefix with reference to Schedule 3 of the National Measurement Regulations 1999 (s 5). Section 7 makes formation of units contingent upon the physical quantities prescribed in the Regulations. Section 9(3) references "an additional derived unit of measurement, mentioned in Part 4 of Schedule 1 to the Regulations", indicating the Regulations include further derived units that the Guidelines authorise to be combined with other Australian legal units. The Guidelines therefore operate in conjunction with the Regulations; the Regulations supply definitional and enumerative content critical to applying the Guidelines.

• Repeal of prior Guidelines: Schedule 1 repeals the whole of the National Measurement Guidelines 2016. That repeal changes the subordinate instrument landscape and means that any references to the 2016 Guidelines in other instruments, guidance or compliance materials will no longer be current; the 2026 Guidelines are the operative rules in place of the 2016 instrument (Schedule 1).

• No express conflicts or overrides: The Guidelines do not state that they override any other law beyond operating under the Act. There is no clause that purports to displace other statutory requirements that might govern labelling, packaging or consumer protection. Therefore, in practice, users will need to reconcile these Guidelines with any other statutory or regulatory obligations that require expression of measurements (for example, laws concerning trade measurement, labelling, consumer information or industry-specific technical standards), noting that the Guidelines are expressly made under the National Measurement Act.

• Referential limits: Several of the Guidelines’ rules depend on content contained in the Regulations (the list of physical quantities, SI prefixes, Part 4 of Schedule 1 to the Regulations). Because the Guidelines do not reproduce those lists, they must be read in tandem with the Regulations. Any change to the Regulations or to Schedule 3 would affect the application of the Guidelines (for example, adding a physical quantity in the Regulations would permit formation of a new Australian legal unit under s 7).

• Administrative actors: The Guidelines are made by the Chief Metrologist, National Measurement Institute (front matter). The National Measurement Institute is the administrative agency that will interpret and implement metrology policy; the text signals that the Guidelines are intended to provide technical direction to that administrative regime. The Guidelines do not confer new legal powers on the Institute but clarify technical compliance expectations.

In practical terms, the Guidelines should be read alongside the National Measurement Act 1960 and the National Measurement Regulations 1999. They are guidance in a mandatory form for unit formation and expression under the Act, and their operation is therefore interconnected with the statutory and regulatory instruments that set out enforcement, scope and definitions.

The instrument itself contains limited material on amendments, but what is present is explicit:

• Date and making: The body of the instrument is dated 9 March 2026 and is made by Dr Victoria Anne Coleman, Chief Metrologist, National Measurement Institute (front matter). The instrument title is National Measurement Guidelines 2026.

• Commencement: The whole of the instrument commences "the day after this instrument is registered" (s 2, Commencement table). The instrument contains the standard note that the commencement table relates only to the provisions as originally made and will not be amended in published versions to reflect later amendments.

• Authority for making: The instrument is made under section 7B of the National Measurement Act 1960 (s 3). That provision is cited as the legal authority for the instrument’s creation.

• Repeal of prior instrument: Schedule 1,Repeals contains a single item: it repeals the whole of the National Measurement Guidelines 2016. The Schedule states "Repeal the instrument" and identifies the instrument to be repealed. This is an express replacement: the 2026 Guidelines supersede the 2016 Guidelines in their entirety (Schedule 1).

• No further amendment history included: The instrument does not list any prior amendments to itself, nor does it include a historical table of prior amendments. The only amendment-related content is the repeal of the 2016 Guidelines.

• Notes on publishing: The Commencement table includes the standard technical note that column 3 information is not part of the instrument and may be edited in any published version. That is an administrative note, not an amendment to the substantive rules.

In short, based on the instrument’s text alone, the amendment history recorded is limited to the repeal of the 2016 Guidelines and the date of making (9 March 2026). There are no other amendments, transitional arrangements, savings clauses or staged commencements recorded in the instrument text.

The Guidelines contain no references to case law, judicial decisions, or any litigation history. The text does not cite, rely on, or summarise any court or tribunal determinations. There are no provisions that purport to implement court-ordered changes or to respond to litigation. The instrument is purely technical and administrative in content.

What the instrument records (or does not record):

• No cases named: The Guidelines do not name any legal cases. The front matter and body include administrative authorship and statutory authority but no judicial references.

• No legal challenges or outcomes recorded: There is no mention of past or pending legal challenges to the Guidelines or to predecessor instruments. The repeal of the 2016 Guidelines is recorded, but the instrument does not indicate whether that repeal follows litigation, consultation outcomes, or policy review.

• Practical implication for researchers and litigators: The absence of litigation references in the Guidelines means that anyone preparing legal argument about the construction or application of these Guidelines must rely on the statutory text, the Regulations and the Act. If litigation arises about compliance or interpretation, the Guidelines themselves will provide the text to be interpreted; there is no pre-existing judicial gloss provided within the instrument.

• Need to consult external sources for jurisprudence: Because the Guidelines do not contain litigation history, to determine whether courts have interpreted similar provisions (for example, earlier Guidelines or aspects of the Regulations or Act), one must consult external jurisprudential materials. The instrument does not direct users to any cases or prior tribunal decisions.

In summary, the Guidelines have no litigation history recorded in their text. The instrument is silent on any past disputes, and any litigation history relevant to these rules must be sought outside the instrument itself.

The text contains several specific and technical rules that may produce operational pitfalls if overlooked. These are matters where small drafting or formatting errors could create non-compliance under the Guidelines. Each point below is grounded in the relevant provision.

• Kilogram and prefixing complexity (s 9(2) and note to s 10(2)): The Guidelines exclude kilogram from s 9(1) (the single-prefix rule) and direct that multiples or submultiples of kilogram should be formed by attaching prefixes to gram. Practically, this means expressions like μkg (microkilogram) are explicitly disallowed and the proper form is 10-6 kg expressed as 1 mg or as prefixes on gram (for instance, mg). The note clarifies that kilogram historically contains a prefix, which is why the rule is necessary. Users who attempt to prefix kilogram directly will breach s 9 and related notes.

• Duplicate "minute" entry in the non-prefix list (s 10(1)): The list of units that must not be combined with SI prefixes contains "minute" twice. The duplicate is in the instrument text; readers should treat "minute" as prohibited from prefixing (regardless of duplication), but the repetition is a drafting eccentricity that could cause confusion in automated parsing or drafting tools.

• Mixed unit types in forbidden list (s 10(1)): The list in s 10(1) includes units that are SI base units, non-SI customary units, compound units and temperature units (for example, kilogram, inch, foot, hectare, degree Celsius). Users must not assume the list is confined to one category,units across categories are present and all are subject to the prohibition on prefixing.

• Tonne prefix rule only permits multiples (s 11): Tonne may only be combined with prefixes that make multiples (e.g., kilotonne). The explicit disallowance of millitonne means software or labels that naively attach any prefix to "tonne" will be non-compliant.

• Single SI Prefix rule applies to derived units and prevents chained prefixes (s 9(1), s 12(11)): The Guidelines prohibit multi-step prefixing, such as attempting to represent 10-9 metres as mµm or chaining prefixes on derived units. Only one SI Prefix may be used to form a multiple of a derived unit (s 12(11)). This affects automated unit-formatting libraries and could require data migration or reformatting.

• Mixing names and symbols prohibited (s 12(1)): The Guidelines prohibit mixing written names and symbols in the same expression (for example, "kilometre/h" is acceptable as "km/h", but not "kilometre/h"). This has implications for templates, documentation and user interfaces that may combine full names and symbols.

• No adjectives or signs (s 12(2)): The prohibition on adding adjectives or signs to a unit name or symbol (example: "Wa cannot be used as the unit of acoustic power") requires careful control of customised or locality-specific unit variants. Any appended adjective to a unit will be non-compliant.

• Prefix symbol placement and spacing (s 12(4) and s 12(18)): SI prefix symbols must be placed immediately before the unit symbol without an intermediate space (e.g., mW not m W). Separately, a space is required after the numeric value and before the unit (e.g., "22 m" not "22m"). These formatting rules intersect; for example, "22 mW" is correct, with a space after the number, and no space between prefix and unit symbol.

• Product symbol ambiguity and allowed separators (s 12(12)-(14)): The product symbol may be a dot (·), a full stop if unambiguous, or a space if the unit symbol is not the same as an SI prefix. The example m·K/W is required to avoid confusion with mK/W (millikelvin per watt). Failure to follow these nuances can generate ambiguous expressions.

• Fraction and exponent rules , do not repeat oblique slash (s 12(15)-(17)): The oblique slash may not be repeated on a line unless parentheses avoid ambiguity. Complex expressions must use negative exponents or parentheses. For example, "m/s/s" is disallowed; the correct forms are "m/s2" or "m s-2" or with parentheses as required. Automation systems should be adjusted to produce unambiguous forms.

• Exception for degrees/minutes/seconds spacing (s 12(19)-(20)): The general rule that a space must follow the numeric value does not apply when expressing numerical values and symbols for degrees, minutes and seconds of geographic coordinates (s 12(19)(a) and example) or for plane angles (s 12(19)(b) and example). This carve-out requires conditional formatting logic where coordinates or plane angles are rendered.

• Dependence on the Regulations for enumerations and definitions (s 5, s 7, s 9(3)): The Guidelines refer the reader to the Regulations for SI Prefix listings (Schedule 3), the physical quantities list, and additional derived units (Part 4 of Schedule 1 to the Regulations). Non-compliance can arise from failing to consult the Regulations and the referenced Schedules.

• Repeal of 2016 Guidelines (Schedule 1): The full repeal means any practice or internal policies that relied on the 2016 Guidelines must be reviewed and revised to match the 2026 Guidelines. Transition considerations are not provided in the instrument, so entities must assess the operational impact themselves.

These gotchas are practical, text-derived traps. They are the points where formatting, software, labelling, or documentation workflows are most likely to produce non-conforming outputs unless they are updated to reflect the precise rules of the 2026 Guidelines.

The Guidelines set specific technical rules; compliance requires operational changes, documentation updates, and possibly software or labelling revisions. Below are concrete, source-grounded steps mapped to the relevant provisions.

1. Confirm the applicable physical quantities (s 7)

   • Consult the National Measurement Regulations 1999 to identify which physical quantities are prescribed. The Guidelines only permit forming Australian legal units for those prescribed quantities (s 7). If your activity involves a quantity not listed in the Regulations, these Guidelines do not authorise forming a new Australian legal unit.

2. Use single SI prefixes only (s 9(1), s 12(11))

   • Form decimal multiples or submultiples of an Australian legal unit by applying exactly one SI Prefix symbol directly before the unit symbol. Do not chain prefixes (for example, do not create expressions like "mµm"). Ensure your software and human-authored templates enforce a single prefix rule.

3. Handle kilogram via gram (s 9(2); note to s 10(2))

   • Do not attach prefixes to "kilogram" directly (avoid μkg). When representing decimal multiples or submultiples associated with kilogram, attach the prefix to "gram" (for example, 1 mg = 10-6 kg). Update unit libraries and data dictionaries to represent submultiples/multiples of kilogram as prefixed gram where appropriate.

4. Do not prefix the units listed in s 10(1)

   • Review the list in s 10(1) and ensure labels, documentation, product specifications and software do not present prefixed forms of these units. The list includes (but is not limited to) kilogram, minute, hour, day, decibel, inch, foot, hectare, ounce, foot/minute, degree, minute, second of arc, radian, steradian and degree Celsius. Remove any occurrences of prefixed forms from templates and code.

5. Limit prefixing of tonne to multiples only (s 11)

   • Ensure "tonne" is only combined with prefixes that create multiples (for example, kilotonne). Do not create submultiple forms like millitonne. Update mass unit mapping and unit-conversion utilities to enforce this constraint.

6. Follow expression and formatting rules (s 12)

   • Do not mix names and symbols in the same expression (s 12(1)). Pick either symbols (preferred for concise technical contexts) or full names, and be consistent.
   • Do not add adjectives or signs to unit names or symbols (s 12(2)). Remove any custom modifiers appended to units.
   • Place SI prefix symbols immediately before unit symbols without intermediate space (s 12(4)). For example, write "km" not "k m".
   • Ensure a space after the numerical value and before the unit symbol (s 12(18)). For example, "22 m", "27 V", "15 °C" (with the exception for degree-minute-second coordinate expressions and plane angles noted below).
   • In fractions, prefer placing the SI prefix in the numerator (s 12(6)(b)); use numerator placement where possible to maintain unambiguous expressions (examples: "km/s" not "mm/µs", "mm/s" not "m/ks").
   • Use only a single SI prefix on derived units (s 12(11)).
   • Use the product symbol rules (s 12(12)-(14)): use a centred dot (·) between unit symbols where required, only use a full stop if the resulting expression is unambiguous, or use a space when the unit symbol is not an SI prefix. For thermal resistivity, use "m·K/W".
   • Avoid repeated oblique slashes; in complex expressions use negative exponents or parentheses to prevent ambiguity (s 12(16)-(17)). For example, use "m s-2" or "m/s2", not "m/s/s".
   • Apply exceptions for degrees/minutes/seconds: The spacing rule in s 12(18) does not apply for geographic coordinates and plane angles (s 12(19)-(20)); format coordinates like "33°43'03.0"S 151°09'37.1"E" as shown in the instrument.

7. Consult the Regulations for SI Prefix list and additional derived units (s 5, s 9(3))

   • The Guidelines refer to Schedule 3 of the Regulations for the SI Prefix list (s 5 definition of SI Prefix). Also, s 9(3) references additional derived units in Part 4 of Schedule 1 to the Regulations. For full compliance, consult those parts of the Regulations to ensure the prefixes and additional derived units you intend to use are authorised.

8. Update documentation, templates and software

   • Revise product labels, safety data sheets, technical manuals, website displays, databases, spreadsheet templates and unit-conversion libraries to conform to the Guidelines’ rules.
   • Implement automated validation rules: enforce single-prefix usage, disallow prefixing of the s 10(1) list, ensure kroner/space rules, ensure prefix placement in fractions, and ensure product symbol choices avoid ambiguous expressions.

9. Train staff and suppliers

   • Educate technical writers, labelling teams, compliance officers, developers and suppliers about the specific prohibitions and formatting rules. Emphasise the kilogram/gram rule, the s 10 list of non-prefixable units, and the division/exponent rules for compound units.

10. Retire references to the 2016 Guidelines (Schedule 1)

• The 2026 Guidelines repeal the 2016 Guidelines (Schedule 1,Repeals). Ensure that internal compliance materials and vendor checklists that previously referenced the 2016 Guidelines are updated to reference the 2026 Guidelines.

11. Maintain a trace to legal instruments

• Keep a reference copy of the National Measurement Act 1960 and the National Measurement Regulations 1999, because the Guidelines operate in conjunction with those instruments (s 3, s 5, s 7). Where the Guidelines refer to Schedule 3 or Part 4 of Schedule 1 to the Regulations, check the Regulations for the authoritative lists.

12. Where in doubt, prefer unambiguous symbolic forms

• When expression choices might be ambiguous (for example, whether to use a dot or full stop for a product symbol), default to the unambiguous centred dot and explicit exponent or parentheses forms as exemplified in s 12(12)-(17).

Following these concrete steps, mapped to the specific sections of the Guidelines, will align an organisation’s use of Australian legal units with the technical requirements set out by the Chief Metrologist in the National Measurement Guidelines 2026.