Miles vs Kilometres
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
US (all road distances), UK (road signs, despite metric trade laws), Liberia, Myanmar. Aviation and shipping use nautical miles, which are different.
Most of the world. Ireland switched from miles to km in 2005.
| Aspect | Miles | Kilometres |
|---|---|---|
| Definition | 1,609.344 metres | SI: 1,000 metres |
| UK road signs | Primary unit | Not used |
| Ireland road signs | Pre-2005 | Post-2005 |
| Running events | Mile race (track) | 5K, 10K, half-marathon (21.1 km) |
Frequently asked
How fast is 60 mph in kph?
60 mph = 96.56 kph. The UK motorway limit of 70 mph = 112.65 kph. Mental shortcut for mph to kph: multiply by 1.6 (or add 60% of the value). 30 mph = 48.3 kph (UK urban limit), 60 mph = 96.6 kph (UK national speed limit on single-carriageway roads).
Why does the UK still use miles?
UK road infrastructure was built around miles. Switching would require replacing every road sign, repainting every road marking, and updating every speedometer. Estimated cost in the 2000s exceeded £750 million.