Metric tonne vs ton (US short ton and UK long ton)
“Ton” is three different weights depending on who wrote the spreadsheet. “Tonne” (metric) is the unambiguous SI one: exactly 1000 kilograms.
Side-by-side
| Name | Definition | Kilograms | Pounds |
|---|---|---|---|
| Metric tonne (t) | SI | 1 000 | ≈ 2 204.62 |
| US short ton | 2000 lb | ≈ 907.185 | 2 000 |
| UK long ton | 2240 lb | ≈ 1 016.05 | 2 240 |
Gap US short ton → tonne: about +10%. Gap long ton → tonne: about −1.6%. Small typos, large invoices.
Where each word appears
- Tonne / metric ton / t — science, most of the world, ISO shipping docs, IPCC-style carbon accounting.
- Ton (US) — US customary short ton in domestic freight and some engineering texts.
- Ton (UK historical) — long ton; still seen in older maritime and imperial references.
- “Ton” in casual speech — meaningless without a locale; ask for kilograms.
Convert with Anvil
# 2 metric tonnes → pounds
curl -s 'https://api.oddlathe.com/v1/units?value=2&from=t&to=lb'
# 2000 lb → kg (US short ton mass)
curl -s 'https://api.oddlathe.com/v1/units?value=2000&from=lb&to=kg'The API’s t is the metric tonne. Convert US/UK tons via pounds (or kg) explicitly so the locale is visible in the request.
Practical checklist
- Normalise imports to kg at the boundary of your system.
- Store the source unit string next to the number in audits.
- In UI copy prefer “tonne (1000 kg)” once, then “t”.
- Do not use the same spreadsheet column for “ton” from a US CSV and “tonne” from an EU CSV without a conversion step.
Related
Unit converter · KB vs KiB / MB vs MiB · Celsius ↔ Fahrenheit ↔ Kelvin · Unix seconds vs milliseconds · Anvil /v1/units · Number base converter
Questions
How many kg in a tonne?
Exactly 1000 kg. That is the metric tonne (symbol t).
How many pounds in a US ton?
2000 lb (short ton) ≈ 907.18 kg.
Is a tonne the same as a ton?
No. Tonne = 1000 kg. US ton = 2000 lb. UK long ton = 2240 lb.
Which ton does Anvil /v1/units use?
Only the metric tonne as unit code t. Convert customary tons through lb or kg.
Why do shipping weights look wrong after a CSV import?
Mixed “ton” locales. Convert every row with an explicit unit column before summing.
Is “metric ton” American spelling for tonne?
Often yes — “metric ton” usually means 1000 kg. Still spell it out once to avoid short-ton mix-ups.
Published .