Meter vs. Metre
“Meter” and “metre” overlap only partly. Cambridge marks metre as the UK spelling of the metric length unit and meter as the US unit form, while “meter” also has separate device senses such as electricity meter.
For the metric length unit, use “meter” in US English and “metre” in UK English; a measuring device is “meter,” including in British English.
Key details
Choose the right form
| Meaning / region | Use | Reason |
|---|---|---|
| Metric length unit in US English | meter | US spelling of the unit. |
| Metric length unit in UK English | metre | UK spelling of the unit. |
| Measuring device in either variety | meter | Device senses remain “meter,” including in British English. |
Quick tests
Unit-or-device test
Does the word name the metric unit of length?
If yes: Choose “meter” for US style or “metre” for UK style.
If no: If it names a measuring device, use “meter.”
Caveat: Do not globally replace every “meter” with “metre” in British text; the regional variation applies to the length-unit sense.
Examples
The path is 100 meters long.
US spelling for the metric length unit.
The path is 100 metres long.
UK spelling for the metric length unit.
The electricity meter is outside the building.
The device sense is spelled “meter.”
Further guidance
Core difference
For the unit of length, Cambridge gives UK “metre” and US “meter”; for a measuring device, the dictionary uses “meter.”
Fast Test
Match the spelling to the regional or house style required by the document, then keep that choice consistent.
Variant Boundary
Do not mechanically replace every “meter” with “metre” in British text, because device senses remain “meter.”
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.
- Meter — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Meter device senses and US use of meter for the metric length unit
- Metre — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Metre identified as the UK metric-length spelling corresponding to US meter