tonne
Enable an AI agent to recognise the tonne as a mass unit, interpret quantities expressed in it, and decide which conversions and comparisons are valid.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise the tonne as a mass unit, interpret quantities expressed in it, and decide which conversions and comparisons are valid.
The tonne (symbol t) is a non-SI unit of mass accepted for use with the SI, defined as exactly 1 000 kilograms (1 megagram).
It can be Recognise explicit tonne and metric-ton designations and normalise their unit identity.; Convert tonne quantities to kilograms using the exact scale relationship.; Resolve or flag ambiguous ton designations before calculation.; Compare and aggregate tonne quantities after checking their referents and reporting bases.; Preserve supplied uncertainty and precision through conversion and presentation.; Route compound, equivalent, force or volume quantities to the appropriate neighbouring model..
Distinguishing features
A tonne represents mass and equals exactly 1000 kilograms; it does not represent a force.
The unit symbol is lowercase t; uppercase T is not an interchangeable spelling of that symbol.
Metric ton denotes the same unit, whereas short ton and long ton denote different mass units; an unqualified ton requires contextual resolution.
A tonne cannot be converted directly to cubic metres without information such as density and relevant material conditions.
Tonne-kilometre, tonne of oil equivalent and tonne of CO2 equivalent carry meanings beyond the bare mass unit and cannot be treated as interchangeable quantities.
Scope
+ The tonne as a non-SI unit of mass accepted for use with the SI
+ Its exact relationship to the kilogram: 1 t = 1000 kg
+ The symbol t, the name tonne and the equivalent name metric ton
+ Disambiguation from short tons, long tons and quantities that use tonne terminology with additional meaning
+ Conversion, comparison and precision handling for mass quantities expressed in tonnes
- The identity, composition and condition of the material being measured
- Weighing instruments, calibration procedures and measurement workflows
- Mass, force, density and volume as independently modelled quantities
- Emissions accounting methods and carbon-dioxide-equivalent calculations
- Freight activity, vessel tonnage and energy-equivalence accounting
- Jurisdiction-specific contractual and regulatory requirements
Characteristics
- Quantity kind
- Mass Determines which quantities may be compared and prevents confusion with force, volume or transport activity.
- Exact kilogram scale
- 1 t = 1000 kg exactly Provides the conversion anchor without introducing conversion-factor uncertainty.
- Unit-system standing
- Non-SI unit accepted for use with the SI Distinguishes acceptance for SI use from being an SI base or derived unit.
- Recognised designation
- tonne; metric ton; symbol t Supports recognition while preserving the difference between explicit metric terminology and ambiguous ton terminology.
- Designation resolution
- Explicit tonne; contextually resolved tonne; unresolved ton designation Controls whether an agent may normalise or convert a supplied quantity.
- Reported mass magnitude
- Numerical value in t, attached to a quantity using this unit Enables calculations while keeping the reported value separate from the unit's exact definition.
- Mass-basis qualifier
- For example: gross, net, wet, dry, unspecified Identifies contextual differences that unit conversion alone cannot resolve.
- Reporting precision
- Reported increment or uncertainty in t, when supplied Prevents an exact unit conversion from being mistaken for an improvement in measurement accuracy.
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 24 questions.
Tonne identity and scale Establishes what the unit denotes and its exact relationship to the kilogram.
An agent needs a stable unit identity before interpreting a tonne-labelled value.
Mass unit identity
Separates the mass unit from objects, measurements and other quantity kinds.
Tonne denotes mass
The tonne is a mass unit; it does not itself identify a material, load or weighing event.
- Does this occurrence denote the mass unit or a particular quantity expressed in that unit? definition
- Is the stated quantity mass, or does surrounding language indicate force, volume or another quantity kind? boundary
Kilogram anchor
Records the exact scale and the tonne's relationship to the SI.
Exact thousand kilograms
One tonne equals exactly 1000 kg, and the tonne is a non-SI unit accepted for use with the SI.
- Does the proposed interpretation preserve the exact relationship 1 t = 1000 kg? definition
- Which authoritative metrology reference will support the unit definition and SI-use status in the researched publication? provenance
Names, symbols and ton ambiguity Recognises tonne terminology and handles competing meanings of ton.
Confusing tonne with another ton unit changes the interpreted mass even when the numerical value is unchanged.
Explicit tonne designations
Handles the unit name, equivalent English terminology and case-sensitive symbol.
Name and symbol recognition
Tonne and metric ton identify this unit; its symbol is lowercase t and must be interpreted in context.
- Is the supplied designation tonne, metric ton or t used explicitly as a mass unit? definition
- Does the surrounding notation establish that t is a unit symbol rather than a variable or another local abbreviation? boundary
Competing ton designations
Keeps ambiguous and explicitly non-metric ton usages distinct from the tonne.
Unqualified ton needs evidence
An unqualified ton does not establish tonne identity; short tons and long tons are distinct units.
- What document definition, source metadata or explicit convention establishes which ton is intended? provenance
- Should conversion remain unresolved until the source confirms whether the quantity uses tonnes, short tons or long tons? action
Tonne quantities and calculation Determines when quantities expressed in tonnes can be converted, compared or combined.
A shared mass unit supports arithmetic but does not establish compatible reporting bases or measurement quality.
Conversion and precision
Applies the exact unit factor while retaining the limitations of the supplied value.
Exact scale, limited measurement
Conversion to kilograms multiplies the numerical value by 1000; supplied absolute uncertainty scales by the same factor without improving measurement accuracy.
- What magnitude, reported precision and uncertainty are supplied for the quantity in tonnes? measurement
- How should the converted value be rounded and displayed to preserve the source's stated precision? action
Comparison and aggregation basis
Checks whether tonne quantities describe compatible masses before arithmetic.
Same unit does not establish same basis
Gross, net, wet and dry mass qualifiers affect what is counted; tonne identity alone cannot reconcile these differences or prevent duplicate counting.
- Do the quantities use compatible mass bases and identifiable material or load boundaries? boundary
- What reconciliation or overlap check is required before these tonne quantities may be compared or added? action
Qualified and neighbouring quantities Identifies where tonne terminology requires additional quantity models or contextual relationships.
Tonne-like labels occur in volume, force, freight and equivalence contexts where bare mass conversion is insufficient.
Mass, force and volume boundaries
Separates the tonne from force units and volume-based quantities.
Cross-quantity conversion needs a relation
Deriving volume from mass requires density and relevant conditions; deriving gravitational force requires an applicable acceleration. Vessel tonnage must be interpreted under its own definition.
- Does a requested conversion cross from mass into volume, force or a vessel-tonnage measure? boundary
- Which density, acceleration or independently defined tonnage relationship would justify the requested calculation? measurement
Compound and equivalent reporting
Preserves additional meaning in transport and equivalence-based quantities.
Qualifiers change calculation rules
Tonne-kilometres express transport activity, tonnes of oil equivalent express energy, and tonnes of CO2 equivalent require an emissions-equivalence basis.
- Is tonne used as a bare mass unit, as part of a compound unit or within an equivalence-based reporting quantity? definition
- Which transport, energy or emissions model must supply the additional meaning before comparison or conversion is permitted? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- metric tonne (t)
- tonne of oil equivalent (toe)
- tonne of coal equivalent (tce)
- deadweight tonne (DWT)
- freight tonne / revenue tonne
- carbon dioxide equivalent tonne (tCO2e)
- assay tonne (AT)
- displacement tonne (naval architecture)
- Which of these kinds and varieties hold for the sense of tonne this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q191118 - item for tonne / metric ton as a unit of mass
- UCUM - t - Unified Code for Units of Measure
- UNECE Rec. 20 / UN/CEFACT Common Code - TNE - international trade unit code for metric ton
- SI Brochure symbol - t - BIPM recommended symbol; not an abbreviation and not T
- Which of these identifiers and schemes hold for the sense of tonne this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- BIPM SI Brochure (CGPM/CIPM): tonne accepted for use with the SI; 1 t = 10^3 kg exactly; symbol t
- 9th CGPM (1948) Resolution 7: unit and symbol defined for the tonne
- ISO 80000-4 Quantities and units - Mechanics: mass units and symbols
- UNECE Recommendation 20: Codes for Units of Measure Used in International Trade (TNE)
- NIST SP 811 / NIST Handbook 44 practice: US name 'metric ton' for the same unit
- Which of these standards and regulation hold for the sense of tonne this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Bulk commodity contracts, bills of lading and customs declarations for grain, ore, coal, cement and similar cargoes priced and shipped per tonne
- Vehicle, axle and crane safe-working-load limits stated in tonnes
- Greenhouse-gas inventories and carbon markets reporting emissions in tCO2e
- Ship deadweight, displacement and cargo capacity in maritime operations
- National energy balances converting fuels to tonnes of oil equivalent (toe)
- Which of these real-world use hold for the sense of tonne this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- mass - exactly 1000 - kg
- mass - exactly 1 - Mg
- mass relative to short ton - approximately 1.10231 - short ton
- mass relative to long ton - approximately 0.984207 - long ton
- Which of these typical measurements hold for the sense of tonne this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Unqualified 'ton' mixed with short ton (2000 lb) or long ton (2240 lb) produces ~10% or ~1.6% mass error in trade, lift plans and emissions
- Symbol collisions: T is tesla; MT can be read as megatesla or metric ton
- Using tonne as a force unit (confusing mass with weight / kilonewton) in structural and lifting calculations
- Assay tonne (about 29-33 g) mistaken for a metric tonne in mining samples
- Which of these failure modes and hazards hold for the sense of tonne this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- SI jurisdictions spell the unit tonne and use symbol t; US customary practice usually says metric ton and reserves unqualified ton for the short ton
- UK and much of the Commonwealth now use tonne in law and trade, while older shipping and naval records still use the long ton of 2240 lb
- Australia typically pronounces tonne as /tɒn/; some UK speakers distinguish the final e
- International oil, grain and carbon statistics standardise on metric tonnes even where domestic industry still quotes short tons
- Which of these regional variation hold for the sense of tonne this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- short ton (US ton) - short ton is 2000 lb = 907.18474 kg; 1 t ≈ 1.10231 short tons
- long ton (UK / imperial ton) - long ton is 2240 lb = 1016.0469088 kg; 1 t ≈ 0.984207 long tons
- megagram (Mg) - identical mass (1 t = 1 Mg exactly); Mg is the coherent SI multiple, t is the accepted non-SI name
- tonne of oil equivalent (toe) - toe is an energy unit (IEA 41.868 GJ), not a mass unit, even though named from a tonne of crude
- assay tonne (AT) - a laboratory sample mass (~29.17 g short AT, ~32.67 g long AT) scaled so milligrams of metal map to troy ounces per ton of ore, not 1000 kg
- Which of these neighbouring kinds and how to tell them apart hold for the sense of tonne this model covers, and on what evidence? provenance
Sources
- Tonne - Definition as 1000 kg, BIPM symbol t, conversions to short and long tons, SI-accepted status, and derived multiples (kt, Mt, Gt).
- tonne (Q191118) - Canonical identifiers: Wikidata Q191118, UCUM t, UN/CEFACT TNE, and exact conversion 1 t = 1000 kg.
- SI Units - Mass - US NIST treatment of the metric ton as 1000 kg / 1 megagram, and kilogram as the SI mass base unit.
- Ton - Distinction of tonne from short ton, long ton, deadweight ton, assay ton, and regional naming of unqualified 'ton'.
- Tonne of oil equivalent - toe as an energy unit (IEA: 41.868 GJ), not a mass unit, despite being named from a tonne of crude.
- tonne (SI general unit definition) - CGPM 1948 / CIPM 1879 origin of the unit and SI Brochure classification as a unit used with the SI.
What the second pass must settle
- Does an existing Vercy world model already own tonne or mass-unit identity, requiring this registry entry to link to it?
- Which authoritative metrology sources and editions should substantiate the exact definition, accepted notation and SI-use status?
- Which abbreviations, prefixed forms and language variants actually occur in the target data, and which can be resolved reliably?
- What evidence threshold should permit contextual resolution of an unqualified ton in the intended workflows?
- Which neighbouring Vercy models own mass-basis reconciliation, vessel tonnage, transport activity and emissions or energy equivalence?