Unit Converter

Convert length, weight, temperature, and all physical units

How to Convert km/h to mph

One km/h is approximately 0.621 mph. This conversion is essential when driving in the US or UK where speed limits are posted in mph, or when comparing vehicle performance specifications between metric and imperial systems.

Conversion Formula

mph = km/h × 0.621371

Quick Reference Table

km/h	mph
10	6.214
30	18.641
50	31.069
80	49.71
100	62.137
120	74.565
200	124.27

How to Use the Unit Converter

The Internet Octopus Unit Converter supports 14 categories and over 100 units. Enter a value and select units to see instant conversion results.

Supported Unit Categories

Length — Millimeter, centimeter, meter, kilometer, inch, foot, yard, mile, nautical mile, and more
Weight / Mass — Milligram, gram, kilogram, ton, pound, ounce, stone, grain, and more
Volume — Milliliter, liter, gallon, quart, pint, cup, fluid ounce, tablespoon, teaspoon, and more
Area — Square meter, square kilometer, acre, hectare, pyeong, and more
Temperature — Convert between Celsius, Fahrenheit, and Kelvin
Speed — Meter/second, kilometer/hour, mile/hour, knot, foot/second, and more
Time — Millisecond, second, minute, hour, day, week, year, and more
Digital Storage — Bit, byte, KB, MB, GB, TB, PB, and KiB, MiB, GiB, TiB, and more
Pressure — Pascal, kilopascal, bar, atmosphere, PSI, mmHg, and more
Energy — Joule, kilojoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, electronvolt, and more
Power — Watt, kilowatt, megawatt, horsepower, and more
Angle — Degree, radian, gradian, turn, and more
Force — Newton, kilonewton, pound-force, kilogram-force, and more
Frequency — Hertz, kilohertz, megahertz, gigahertz, and more

How to Use

Enter a number in the left input field.
Select the source unit from the left dropdown.
Select the target unit from the right dropdown — only compatible units are shown.
The result appears instantly. Use the swap button to reverse the conversion.