Miles per hour to Kilometres per hour Converter (mph to km/h)
Convert miles per hour to kilometres per hour instantly. 1 mph = 1.609 km/h. Includes the formula, a full conversion table and a calculator that works offline.
The formula
To convert miles per hour to kilometres per hour, multiply by 1.609:
km/h = mph × 1.609Going the other way, divide instead — or multiply by 0.6214, which is the same thing:
mph = km/h × 0.6214Miles per hour to Kilometres per hour conversion table
| Miles per hour | Kilometres per hour |
|---|---|
| 1 mph | 1.609 km/h |
| 2 mph | 3.219 km/h |
| 3 mph | 4.828 km/h |
| 4 mph | 6.437 km/h |
| 5 mph | 8.047 km/h |
| 6 mph | 9.656 km/h |
| 7 mph | 11.265 km/h |
| 8 mph | 12.875 km/h |
| 9 mph | 14.484 km/h |
| 10 mph | 16.093 km/h |
| 15 mph | 24.14 km/h |
| 20 mph | 32.187 km/h |
| 25 mph | 40.234 km/h |
| 30 mph | 48.28 km/h |
| 40 mph | 64.374 km/h |
| 50 mph | 80.467 km/h |
| 75 mph | 120.7 km/h |
| 100 mph | 160.93 km/h |
| 250 mph | 402.34 km/h |
| 500 mph | 804.67 km/h |
| 1000 mph | 1,609.34 km/h |
Kilometres per hour to Miles per hour
| Kilometres per hour | Miles per hour |
|---|---|
| 1 km/h | 0.6214 mph |
| 2 km/h | 1.243 mph |
| 3 km/h | 1.864 mph |
| 4 km/h | 2.485 mph |
| 5 km/h | 3.107 mph |
| 6 km/h | 3.728 mph |
| 7 km/h | 4.35 mph |
| 8 km/h | 4.971 mph |
| 9 km/h | 5.592 mph |
| 10 km/h | 6.214 mph |
What that actually looks like
A conversion factor is hard to judge on its own. These are quantities most people already have a feel for, converted for you:
- A brisk walk is 3 mph — 4.828 km/h
- A US residential limit is 25 mph — 40.234 km/h
- A US highway limit is 70 mph — 112.65 km/h
Why both units are still in use
Speed limits are posted in miles per hour in the US and UK and in kilometres per hour nearly everywhere else, which makes this a conversion drivers do in their heads on holiday. Aviation and shipping use knots, a third unit entirely, because a knot is one nautical mile per hour and a nautical mile maps neatly onto a minute of latitude.
Mistakes worth avoiding
The rough mental shortcut of adding a half — 50 km/h is about 30 mph — drifts badly at higher speeds. At motorway speeds it is off by enough to matter, so use the real factor when a speed limit is involved.
The other habit worth breaking is rounding too early. Convert first, round once at the end, and you avoid the drift that turns a small approximation into a visible error by the third calculation.
Doing it in your head
When you only need a rough answer, multiply by 8 and divide by 5 — which lands within 0.6 percent of the true value. Ten miles per hour works out at roughly 16 kilometres per hour that way, against 16.093 exactly. An estimate is enough for deciding whether something will fit or whether a figure sounds plausible. When the number has to be right — because you are buying, cooking or building to it — use the calculator and let it carry the decimals.
Common questions
How many kilometres per hour are in one miles per hour?
One miles per hour equals 1.609 kilometres per hour. The calculator above handles any value, including decimals and very large numbers, and updates as you type.
Is this an exact conversion?
Yes — this is an exact defined ratio, not an approximation. The table rounds for readability; the calculator does not.
Does this work offline?
Yes. The conversion runs in your browser with no network request, so it works on a plane, in a basement, or on a phone with no signal once the page has loaded.