Multiply by 1,000 — the factor is exact
metres = kilometres × 1000, kilometres = metres ÷ 1000
"Kilo" means a thousand, so a kilometre is 1,000 metres by definition, not by measurement. In practice you just shift the decimal three places: 2.5 km → 2,500 m; 300 m → 0.3 km.
Quick reference
| Kilometres | Metres |
|---|---|
| 0.1 km | 100 m |
| 0.5 km | 500 m |
| 1 km | 1,000 m |
| 5 km | 5,000 m |
| 10 km | 10,000 m |
| 42.195 km | 42,195 m (marathon) |
Use kilometres for road distances and races, metres for room sizes, pool lengths and heights. Both are SI units, so the conversion never changes with temperature or altitude.
Common questions
How many metres are in a kilometre?
Exactly 1,000. The prefix "kilo" means one thousand, so one kilometre is 1,000 metres by definition — there is no rounding involved.
How do I convert km to m in my head?
Move the decimal point three places to the right, or just add three zeros. So 2.5 km is 2,500 m and 0.75 km is 750 m.
How many metres is a marathon?
A marathon is 42.195 km, which is 42,195 metres. A 5K is 5,000 m and a 10K is 10,000 m.
