Speed Converter

1 mph = 1.60934 km/h · 1 knot = 1.852 km/h

Speed, Time & Data

How to Use This Tool

Speed converter

Type a value into any field and the converter calculates the rest. It covers miles per hour, kilometers per hour, meters per second, feet per second, and knots. These are the units you run into when driving, running, sailing, or checking weather reports in different countries.

Common speed conversions

From To Multiply by
Miles per hour (mph) Kilometers per hour (km/h) 1.60934
Kilometers per hour (km/h) Miles per hour (mph) 0.62137
Miles per hour (mph) Meters per second (m/s) 0.44704
Kilometers per hour (km/h) Meters per second (m/s) 0.27778
Meters per second (m/s) Kilometers per hour (km/h) 3.6
Knots (kn) Miles per hour (mph) 1.15078
Knots (kn) Kilometers per hour (km/h) 1.852
Miles per hour (mph) Feet per second (ft/s) 1.46667
Feet per second (ft/s) Miles per hour (mph) 0.68182
Meters per second (m/s) Miles per hour (mph) 2.23694

Speed conversion formulas

Miles per hour to kilometers per hour

km/h = mph x 1.60934

Example: 60 mph x 1.60934 = 96.6 km/h. That is roughly the highway speed limit in many European countries.

Kilometers per hour to miles per hour

mph = km/h x 0.62137

Example: 100 km/h x 0.62137 = 62.1 mph.

Miles per hour to meters per second

m/s = mph x 0.44704

Example: 30 mph x 0.44704 = 13.4 m/s. Physics problems and wind speed reports often use meters per second.

Knots to miles per hour

mph = knots x 1.15078

Example: 25 knots x 1.15078 = 28.8 mph. Nautical and aviation speeds are reported in knots.

Knots to kilometers per hour

km/h = knots x 1.852

Example: 10 knots x 1.852 = 18.52 km/h.

When you need speed conversions

Driving abroad

The US, UK, and a few other countries post speed limits in miles per hour. Most of the world uses kilometers per hour. A 120 km/h sign on a European highway means 74.6 mph. A 70 mph British motorway limit is 112.7 km/h. Renting a car in a country that uses the other system means doing these conversions constantly, or at least once to calibrate your speedometer reading.

Aviation and sailing

Pilots and sailors measure speed in knots. One knot is one nautical mile per hour, and a nautical mile is 1.852 km (1.151 statute miles). Air traffic control, weather reports for mariners, and nautical charts all use knots. A small craft advisory might warn of winds above 20 knots, which is 23 mph or 37 km/h.

Running and athletics

Treadmills in the US display speed in mph. Race results and training plans outside the US use km/h or minutes per kilometer. A 6:00 min/mile pace is 10 mph or 16.1 km/h. A 5:00 min/km pace is 12 km/h or 7.5 mph. Runners switching between metric and imperial paces need these conversions regularly.

Weather and wind

US weather forecasts give wind speed in mph. International forecasts use km/h or m/s. The Beaufort scale, used in marine forecasts, maps to specific speed ranges. A “fresh breeze” is 19 to 24 mph, 29 to 38 km/h, or 17 to 21 knots. Hurricane force starts at 74 mph (119 km/h, 64 knots).

Common speeds for reference

Activity or object mph km/h m/s
Walking 3.1 5 1.4
Jogging 6 9.7 2.7
Cycling (casual) 12 19.3 5.4
City speed limit (US) 25 40.2 11.2
Highway speed limit (US) 65 104.6 29.1
Cheetah (top speed) 70 112.7 31.3
Commercial airplane 575 925.4 257.1
Speed of sound (sea level) 767 1,234.8 343

Tips for accurate conversions

  • For a quick mph to km/h estimate, multiply by 1.6. So 50 mph is roughly 80 km/h, and 100 mph is about 160 km/h. Going the other way, multiply km/h by 0.6.
  • Knots and nautical miles are based on the geometry of the Earth. One nautical mile is one minute of latitude. This is why aviation and maritime navigation still use them despite most other fields switching to metric.
  • Wind speed units vary by country and context. The US National Weather Service uses mph for public forecasts and knots for marine advisories. International meteorology uses m/s or km/h. Always check which unit a forecast is using before comparing numbers.
  • Mach numbers describe speed relative to the speed of sound, which changes with altitude and temperature. Mach 1 at sea level in standard conditions is 767 mph (1,235 km/h), but at 35,000 feet it drops to about 660 mph (1,062 km/h) because the air is colder.

Frequently asked questions

How many km in a mile?

1 mile = 1.60934 km. So 1 mph = 1.60934 km/h.

How fast is 100 km/h in mph?

100 km/h = 62.1 mph.

What is a knot?

A knot is one nautical mile per hour. One knot equals 1.15078 mph or 1.852 km/h. The name comes from the old practice of counting knots on a rope dragged behind a ship to measure speed.

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

Multiply by 3.6. So 10 m/s = 36 km/h.

What is the speed of light?

About 299,792,458 m/s, or 670,616,629 mph, or 1,079,252,849 km/h. Nothing with mass can reach this speed.

How fast is Mach 1?

At sea level in standard conditions, Mach 1 is 767 mph (1,235 km/h, 343 m/s). It varies with temperature and altitude.

How do I convert pace (min/mile) to speed (mph)?

Divide 60 by the pace in minutes. A 10-minute mile is 60/10 = 6 mph. A 7:30 pace is 60/7.5 = 8 mph.

Why do ships and planes use knots instead of mph or km/h?

Knots tie directly to nautical miles, which are based on the Earth\’s latitude lines. One degree of latitude is 60 nautical miles. This makes navigation calculations simpler when working with coordinates on a chart.

Measurement guides

Formula & Explanation

Speed conversions combine a distance conversion with a time conversion. The knot is defined as exactly 1 nautical mile per hour, where 1 nautical mile = 1852 m exactly.

Frequently Asked Questions

How fast is 60 mph in km/h?

60 mph = 60 u00d7 1.60934 = 96.56 km/h. This is a common highway speed limit in the US.

What is a knot?

A knot is one nautical mile per hour. 1 knot = 1.852 km/h = 1.15078 mph. Knots are used in aviation and maritime contexts because nautical miles are the standard distance unit on water and in the air.

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

Multiply by 3.6. For example, 10 m/s = 36 km/h. This works because 1 m/s = 3.6 km/h.