Speed converter

km/h, mph, metres per second, knots and feet per second, converted both ways with exact factors.

Fromkilometre per hour (km/h)

Tomile per hour (mph)

0.6213711922

DecimalsAuto (up to 10 significant digits)

Formula: mph = km/h × 0.621371192237

1 km/h = 0.6213711922 mph

Common values: kilometre per hour to mile per hour

km/h	mph
5 km/h	3.106855961 mph
10 km/h	6.213711922 mph
20 km/h	12.42742384 mph
30 km/h	18.64113577 mph
40 km/h	24.85484769 mph
50 km/h	31.06855961 mph
60 km/h	37.28227153 mph
80 km/h	49.70969538 mph
100 km/h	62.13711922 mph
120 km/h	74.56454307 mph
140 km/h	86.99196691 mph
200 km/h	124.2742384 mph

How it works

Road signs use km/h almost everywhere except the US and UK (mph); weather services report wind in m/s, km/h or knots depending on the country; pilots and sailors work in knots; physics problems want metres per second. This converter handles all five units.

All factors are exact: 1 mph = 1609.344 m per 3600 s = 1.609344 km/h = 0.44704 m/s; 1 knot = 1852 m per hour = 1.852 km/h; 1 km/h = 1/3.6 m/s; 1 ft/s = 0.3048 m/s. So to go from m/s to km/h, multiply by 3.6.

A quick mental check: 100 km/h is about 62 mph, and 30 knots is about 55.6 km/h or 34.5 mph.

Common speed conversions

Road speeds use km/h or mph, science uses metres per second, and ships and aircraft use knots (nautical miles per hour).

1 km/h = 0.6213711922 mph (mph = km/h × 0.621371192237)
1 mph = 1.609344 km/h (km/h = mph × 1.609344)
1 m/s = 3.6 km/h (km/h = m/s × 3.6)
1 kn = 1.852 km/h (km/h = kn × 1.852)
1 kn = 1.150779448 mph (mph = kn × 1.15077944802)
1 ft/s = 0.3048 m/s (m/s = ft/s × 0.3048)

Every speed unit in this converter

The size of each unit in metre per seconds (m/s), the base unit the converter uses internally. Values are exact where the unit has an exact definition.

Unit	In m/s
metre per second (m/s)	1 m/s
kilometre per hour (km/h)	0.2777777778 m/s
mile per hour (mph)	0.44704 m/s
knot (nautical mile per hour) (kn)	0.5144444444 m/s
foot per second (ft/s)	0.3048 m/s

How to use it

Choose the speed unit you have and the one you need.
Type a value in either box and read the other.
Use the table for a range of common speeds.

Frequently asked questions

How do I convert m/s to km/h?

Multiply by 3.6 (there are 3600 seconds in an hour and 1000 metres in a kilometre). A wind of 10 m/s is 36 km/h.

What is a knot?

One nautical mile per hour, exactly 1.852 km/h or about 1.1508 mph. Aviation, marine forecasts and wind reports for sailors use knots.

How many km/h is 60 mph?

60 × 1.609344 = 96.56 km/h. The mph-to-km/h page has a full table of common speed limits.

Does it convert Mach numbers?

No. Mach is a ratio to the local speed of sound, which depends on air temperature (about 343 m/s at 20 °C at sea level), so it is not a fixed unit.