Convert km/h to mph in one click
Type any speed in kilometres per hour and get the exact miles per hour result instantly. Perfect for reading car specs, understanding speed limits abroad, or checking a runner's or cyclist's pace.
Quick fact: 100 km/h = 62.14 mph — the single most-searched conversion for this pair. The reverse works too: enter mph above to get km/h back.
KMH to MPH reference table
Common kmh to mph conversions at a glance. Formula: mph = km/h × 0.621371.
| km/h | mph |
|---|---|
| 1 km/h | 0.621 mph |
| 2 km/h | 1.243 mph |
| 5 km/h | 3.107 mph |
| 10 km/h | 6.214 mph |
| 25 km/h | 15.534 mph |
| 50 km/h | 31.069 mph |
| 100 km/h | 62.137 mph |
To go the other way, use km/h = mph × 1.60934. The converter above handles both directions.
How to use the converter
- Enter your speed in the km/h field at the top of the page.
- The mph result updates instantly — no button needed.
- Want mph to km/h instead? Flip the direction in the converter and type your mph value.
- Copy or note the result. Done.
Worked example: converting 120 km/h to mph
Say you rented a car in Europe and the motorway limit is 120 km/h. How fast is that in miles per hour?
Step 1 — Apply the conversion factor:
mph = km/h × 0.621371
mph = 120 × 0.621371
mph = 74.56Result: 120 km/h = 74.56 mph. That is just under 75 mph, well within a UK 70 mph motorway limit — good to know before you drive.
How the calculation works
One mile equals exactly 1.60934 kilometres (set by international agreement). So one kilometre is 1 ÷ 1.60934 = 0.621371 miles. That ratio is the conversion factor.
mph = km/h × 0.621371
km/h = mph × 1.60934The table below shows a few more conversions to make the pattern obvious:
| Situation | km/h | mph |
|---|---|---|
| City speed limit (common in Europe) | 50 km/h | 31.1 mph |
| Typical motorway cruise | 130 km/h | 80.8 mph |
| Formula 1 top speed (approximate) | 370 km/h | 229.9 mph |
| Average walking pace | 5 km/h | 3.1 mph |
| Recreational cycling | 25 km/h | 15.5 mph |
Speed, velocity, and how people phrase the same question
People ask this in lots of ways — they all mean the same conversion:
- "kph to mph" — kph and km/h are the same unit, just written differently.
- "kilometres per hour to miles per hour" — the long-form version.
- "convert speed from metric to imperial" — km/h is the metric unit; mph is the imperial (used mainly in the US and UK).
- "how fast is X km/h in mph?" — just plug X into the tool above.
If you see m/s (metres per second) on a weather or science app, that is a different unit altogether. Multiply m/s by 3.6 to get km/h first, then convert.
Quick tips and common mistakes
- Don't multiply by 0.6 and call it done. The real factor is 0.621371. Using 0.6 gives an error of about 3.5% — that adds up at high speeds.
- The "times 5, divide by 8" shortcut (e.g. 80 km/h → 80 × 5 ÷ 8 = 50 mph) is a handy mental-maths trick accurate to about 1%.
- Watch your units: sat-nav apps sometimes show m/s or knots. They are not the same as km/h.
- Speed limits are legal limits, not targets. Always check local road rules when driving abroad.
- For very precise engineering use, stick to the full factor: 0.621371192.
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Bottom line: multiply any km/h value by 0.621371 and you have mph — or just use the converter above and skip the maths entirely.