Liter vs. Litre
“Liter” and “litre” name the same metric volume unit. Cambridge marks liter as the US spelling and litre as the UK form.
Use “liter” in US English and “litre” in UK English for the metric volume unit.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| US spelling | liter | Use the US form. |
| UK spelling | litre | Use the UK form. |
Quick tests
Meaning / construction test
Does the document follow US spelling?
If yes: Use “liter.”
If no: Use “litre” for UK spelling or the required house style.
Caveat: The two spellings name the same metric unit; consistency with regional or house style is the main choice.
Examples
The tank holds five liters.
US spelling uses “liter.”
The tank holds five litres.
UK spelling uses “litre.”
Use one litre throughout this UK-facing manual.
The spelling is consistent with the audience.
Further guidance
Core difference
The pair is a regional spelling difference for the metric unit of volume.
Fast Test
Match the spelling to the regional or house style required by the document, then keep that choice consistent.
Variant Boundary
Do not treat one form as universally misspelled; use the regional or house style required.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Liter — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Liter identified as the US spelling of litre
- Litre — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Litre identified as the UK form corresponding to US liter