km/h to mph Converter

kilometres per hour to miles per hour formula

mph = km/h ÷ 1.609344

1 kilometre per hour = 0.6213711922 miles per hour, so multiply kilometres per hour by 0.6213711922. Going the other way, 1 mile per hour = 1.609344 kilometres per hour.

kilometres per hour to miles per hour table

How many miles per hour in kilometres per hour?

1 km/h = 0.621371 mph. There are 0.621371 miles per hour in 1 kilometres per hour.

30 km/h = 18.6411 mph. There are 18.6411 miles per hour in 30 kilometres per hour.

50 km/h = 31.0686 mph. There are 31.0686 miles per hour in 50 kilometres per hour.

100 km/h = 62.1371 mph. There are 62.1371 miles per hour in 100 kilometres per hour.

130 km/h = 80.7783 mph. There are 80.7783 miles per hour in 130 kilometres per hour.

miles per hour to kilometres per hour formula

km/h = mph × 1.609344

1 mile per hour = 1.609344 kilometres per hour, so multiply miles per hour by 1.609344, or divide by 0.6213711922.

miles per hour to kilometres per hour table

How many kilometres per hour in miles per hour?

1 mph = 1.60934 km/h. There are 1.60934 kilometres per hour in 1 miles per hour.

30 mph = 48.2803 km/h. There are 48.2803 kilometres per hour in 30 miles per hour.

60 mph = 96.5606 km/h. There are 96.5606 kilometres per hour in 60 miles per hour.

70 mph = 112.654 km/h. There are 112.654 kilometres per hour in 70 miles per hour.

100 mph = 160.934 km/h. There are 160.934 kilometres per hour in 100 miles per hour.

How the Km/h To Mph works

Speed signs change at the border but cars, sat-navs and running watches often don't. A British hire car in France shows mph on a road signed in km/h; a Garmin set to metric reports a run in km/h when the training plan is written in miles. The conversion is simple and exact, and the harder part is knowing which figures are worth remembering.

The km/h to mph formula

The hour is the same on both sides, so converting speed is just converting distance. Since 1959, the international mile has been defined as exactly 1,609.344 metres, so:

mph = km/h ÷ 1.609344, or km/h × 0.621371

km/h = mph × 1.609344

For mental arithmetic, multiply km/h by 0.6 and add a little, or take five-eighths. Going the other way, multiply mph by 1.6. Both shortcuts are within 3 % at any road speed, closer than a car speedometer is required to be.

Example: a French motorway. 130 × 0.621371 = 80.8 mph. That is the limit on French and Italian autoroutes in dry weather. In rain, France drops it to 110 km/h, which is 68.4 mph, just under the British 70.

Example: a UK 30 mph street. 30 × 1.609344 = 48.3 km/h. Most of Europe signs its towns at 50 km/h, which is 31.1 mph, so a British driver abroad can treat the two as the same limit. The 20 mph zones that became the Welsh default in September 2023 are 32.2 km/h, a touch faster than the 30 km/h zones spreading across European city centres.

Example: a treadmill. A run at 10 km/h is 6.2 mph. Divide 60 by the speed for pace: 60 ÷ 10 is a six-minute kilometre, and 60 ÷ 6.21 is a 9:39 mile.

How many mph is that speed limit?

Common speeds in both units, from walking pace to cruising altitude

France lowered most two-lane rural roads from 90 to 80 km/h in 2018, and some departments have since moved back to 90, so check the signs rather than the table. The Autobahn figure is the recommended speed, the Richtgeschwindigkeit; many stretches have no limit at all.

Reading the result

• "X km/h equals" is the converted speed to ten significant figures, with trailing zeros dropped, so 100 km/h shows as 62.13711922 mph. Round it to suit the job.
• Conversion states the factor for the direction you are converting: 1 km/h = 0.621371 mph, or 1 mph = 1.60934 km/h after pressing swap.
• Inverse gives the factor the other way, handy when you want to check a figure by multiplying back.

The two tables under the converter step through round numbers in each direction, and the "how many" lines answer the questions people search for most, like 100 km/h in mph and 70 mph in km/h.

Where the two units meet

The UK is the only country in Europe still signing roads in miles per hour, along with the US, Liberia and a handful of territories. Ireland switched to km/h in January 2005 and changed 58,000 signs over one weekend. UK cars show both scales on the speedometer, but many digital dashboards only show one at a time, set in a menu. Motorsport splits the same way: Formula 1 reports speeds in km/h, while IndyCar and NASCAR use mph.

Tips and pitfalls

• Round down when driving. Converting a limit and rounding up is how speeding tickets happen. 80 km/h is 49.7 mph, so hold 49, not 50.
• Speedometers read high. UN ECE Regulation 39 lets a speedometer overstate, never understate, by up to 10 % plus 4 km/h. A car showing 130 km/h may really be doing 122. GPS speed on a sat-nav is usually closer to the truth.
• Don't confuse km/h with knots. A knot is a nautical mile per hour, 1.852 km/h, so 20 knots is 37 km/h or 23 mph. Wind forecasts at sea and aviation speeds use knots.
• Metres per second for physics. Divide km/h by 3.6: 36 km/h is 10 m/s. Wind speeds in weather data and sprint speeds are usually quoted this way.

For the other speed units, use m/s to km/h, km/h to knots or knots to mph. Distances convert with km to miles, and a run exported from a watch turns into splits with the GPX pace calculator.

Sources: NIST unit conversion.

Checked against: 100 km/h = 62.14 mph

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