Miles per hour to Kilometers per hour Converter
Convert Miles per hour (mph) to Kilometers per hour (km/h) instantly, or use the conversion table below to look up common values.
Miles per hour to Kilometers per hour conversion table
| Miles per hour (mph) | Kilometers per hour (km/h) |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 3 | 4.828032 |
| 4 | 6.437376 |
| 5 | 8.04672 |
| 10 | 16.09344 |
| 25 | 40.2336 |
| 50 | 80.4672 |
| 100 | 160.9344 |
How to convert Miles per hour to Kilometers per hour
1 mph equals 1.609344 km/h. Use the converter above for any value, or read the table for common conversions.
km/h = mph × 1.6093439999999999 · mph = km/h × 0.6213711922373341Multiply a miles per hour figure by 1.609344 to get kilometers per hour, or divide it by 0.621371 to go the other way.
Worked examples
- 1 mph= 1.609344 km/h
- 5 mph= 8.04672 km/h
- 10 mph= 16.09344 km/h
- 30 mph= 48.28032 km/h
- 50 mph= 80.4672 km/h
What these units are
Miles per hour (mph). A mile per hour is 0.44704 meters per second. It is the road-speed unit in the United States and the United Kingdom, and appears on imported vehicle speedometers.
Kilometers per hour (km/h). A kilometer per hour is 0.277778 meters per second. It is the unit on road signs and vehicle speedometers in Tanzania and most countries.
The 3.6 factor between m/s and km/h is exact, so those two convert losslessly. Knots and miles per hour are exact definitions as well.
Converting Miles per hour to Kilometers per hour in practice
Working in miles per hour
A mile per hour is one statute mile, exactly 1,609.344 meters, travelled in one hour. Miles per hour and kilometers per hour relate by exactly 1.609344, and one mile per hour is exactly 0.44704 meters per second.
It is used on road signs and in vehicle speed limits, in motoring and tyre specifications, in wind and weather reports, and in aviation and motorsport figures.
One mile per hour is exactly 1.609344 km/h, and that metric relationship needs no rounding. A knot is not a mile per hour, since one uses the nautical mile of 1,852 meters and the other the statute mile.
Treating a mile per hour as a knot is the usual mistake, because both count distance over an hour. A vessel or aircraft figure in knots needs the nautical mile before it can be compared with road speed.
The siblings are kilometers per hour, knots and meters per second. Posted road speeds in miles per hour belong to this unit, metric road and wind figures belong to kilometers per hour, navigation belongs to knots, and scientific measurement belongs to meters per second.
Reading the result in kilometers per hour
Kilometers per hour measures how many kilometers are covered in one hour. The relationship with meters per second is exact: 1 m/s is exactly 3.6 km/h, so the two units differ by a fixed factor of 3.6.
The unit appears on road signs and in vehicle speed limit legislation, in wind and weather reports, in cycling and motoring specifications, and in everyday estimates of travel time over a known distance.
The metric relationships are exact, since 1 m/s is exactly 3.6 km/h and dividing a km/h value by 3.6 returns m/s. A knot is not a mile per hour, because the nautical mile and the statute mile are different lengths.
The usual error is reading a km/h figure as miles per hour, or treating a knot as a mile per hour because both describe distance over an hour. The unit label decides which conversion applies.
Miles per hour and knots are the siblings most easily confused with kilometers per hour. Kilometers per hour carries road postings and weather reports, miles per hour appears where signs are posted in that unit, and knots governs sea and air navigation.
Checking a miles per hour to kilometers per hour conversion
Every speed unit is a distance over a time, so the conversion factor is just the distance factor divided by the time factor. Meters per second to kilometers per hour is a single multiplication by exactly 3.6, and a reader can hold that number.
The candidates for confusion are the mile and the nautical mile, because both appear in speed units. A knot is one nautical mile per hour, and a nautical mile is 1,852 meters against the statute mile's 1,609.344, so a knot is about 15% faster than a mile per hour. Treating the two as interchangeable understates a marine or aviation speed.
To check a speed conversion, convert it to meters per second and compare with something known, such as walking pace. The error to avoid is applying the 3.6 factor to a pair that is not m/s to km/h, when the correct move is to convert the distance and the time separately.
Tanzania reference points
Real quantities, converted into the units on this page.
The speed limit in built-up areas in Tanzania
50 km/h = 31.06856 mph
Source: Road Traffic Act [Cap.168 R.E 2002] s.51, summarised by FB Attorneys · verified 2026-09-14
The maximum speed outside built-up areas for vehicles over 3,500 kg in Tanzania
80 km/h = 49.709695 mph
Outside built-up areas the limit for other vehicles is set by posted signs and road markings rather than a single national figure.
Source: Road Traffic Act [Cap.168 R.E 2002] s.51, summarised by FB Attorneys · verified 2026-09-14
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