How do I convert km/h to mph?

Multiply by 0.621371. 100 km/h is 62.14 mph.

One nautical mile per hour, which is 1.852 km/h.

It depends on temperature and altitude, so it is not a fixed speed and is not included here.

Speed Converter

Convert km/h, mph, m/s, knots and feet per second.

Updated September 19, 2026Checked by the editorial team

Value

From

Kilometers per hour to Miles per hour

0.621371 mph

1 km/h = 0.621371 mph

Decimal places

Show 1 km/h in every unit

Unit	Value
Meters per second	0.277778 m/s
Miles per hour	0.621371 mph
Knots	0.539957 kn
Feet per second	0.911344 ft/s

Speed limits, running paces, wind forecasts and boat speeds are all quoted in different units. This converter handles kilometers per hour, miles per hour, meters per second, knots and feet per second.

Enter a value, pick the units and the result updates immediately.

How speed converter works

Speeds are converted through meters per second. One mile per hour is exactly 0.44704 m/s, one kilometer per hour is 1/3.6 m/s, and a knot is one nautical mile per hour, or 1,852/3,600 m/s.

The formula

km/h → mph: multiply by 0.621371
mph → km/h: multiply by 1.609344
m/s → km/h: multiply by 3.6
1 knot = 1.852 km/h = 1.15078 mph

Worked example: road, wind and sprint

A limit of 100 km/h is 62.1 mph, and 60 mph is 96.6 km/h.

A wind of 20 knots is 20 × 1.852 = 37 km/h.

A 100 m sprint in 10 seconds averages 10 m/s, which is 36 km/h.

Quick reference

From	To
1 m/s	3.6 km/h (2.23694 mph)
1 km/h	0.621371 mph
1 mph	1.609344 km/h
1 knot	1.852 km/h (1.15078 mph)
1 ft/s	1.09728 km/h

When to use this converter

Driving abroad and reading unfamiliar speed limits.
Interpreting marine and aviation weather in knots.
Converting pace and sports speeds.

Common mistakes to avoid

Using 1.6 for km to mile conversions on large values. It drifts, so use 1.609344.
Confusing knots with mph. A knot is about 15% faster than a mile per hour.
Mixing speed and pace. Minutes per kilometer is pace, not speed.

Frequently asked questions

How do I convert km/h to mph?: Multiply by 0.621371. 100 km/h is 62.14 mph.
How do I convert m/s to km/h?: Multiply by 3.6.
What is a knot?: One nautical mile per hour, which is 1.852 km/h.
How fast is Mach 1?: It depends on temperature and altitude, so it is not a fixed speed and is not included here.

Learn more

Results are for information only and are not financial, legal or medical advice. The calculation logic is covered by automated tests, and examples on this page are worked out and re-checked before publishing. Spotted a mistake? Tell us.