Convert between mph, km/h, m/s, knots and feet per second instantly. This free speed converter needs no signup and runs entirely in your browser.
What is the Speed Converter?
A speed converter translates velocity between the units used on roads, in the air and at sea. Convert miles per hour to kilometers per hour for foreign road trips, knots to km/h for sailing and aviation, or meters per second to mph for sports and science — instantly and precisely.
Five units cover the common cases: meters per second (the scientific standard), kilometers per hour (most of the world’s road signs), miles per hour (US and UK roads), knots (aviation and maritime, defined as one nautical mile per hour), and feet per second (ballistics and some engineering). Enter a value once and convert to any of the others.
It is free with no signup and runs entirely in your browser. Travelers read foreign speed limits correctly, runners compare paces, sailors and pilots convert winds and airspeeds, and students check physics homework without arithmetic slips. Speed limits, wind reports and race paces all speak different unit languages depending on where you stand — this tool translates fluently between them. Getting the conversion right matters: misreading a foreign speed limit is an expensive mistake.
How to use the Speed Converter
- Enter the speed value you want to convert.
- Choose the unit you are converting from — mph, km/h, m/s, knots or ft/s.
- Choose the unit to convert to and read the instant result.
- Adjust the value or swap units to explore conversions in both directions.
- Use the result directly: road speeds, wind speeds, pace and velocity problems.
Speed Converter use cases
Driving abroad
A 130 km/h limit in France is about 81 mph; a 65 mph US limit is about 105 km/h. Convert signposted limits to the units your speedometer shows to avoid tickets.
Running and cycling
Runners convert min/km pace to mph, cyclists compare km/h averages with mph-based training plans, and everyone understands race speeds in familiar units. Elite marathon pace — about 20 km/h — sounds even more impressive converted to a 2:55 min/km.
Sailing and aviation
Wind speeds, boat speeds and airspeeds are given in knots. Convert to km/h or mph to brief passengers and plan passages in relatable terms. A 25-knot wind is a pleasant sail for some boats and a no-go for others — know your number.
Weather
Storm reports in knots or m/s become mph or km/h for understanding how strong the wind really is where you live. Hurricane categories are defined by wind speed, so conversion turns categories into felt reality.
Science and homework
Physics problems mix m/s, km/h and ft/s freely. Instant conversion lets students focus on the concepts instead of arithmetic. Dimensional analysis practice: convert first, then check the units cancel correctly.
Tips
- A knot is exactly one nautical mile per hour (1.852 km/h) — it is a speed, not a distance.
- Speedometer error and GPS lag matter more than conversion rounding: treat converted limits as guidance and drive to conditions.
- For pace (minutes per kilometer) rather than speed, convert the speed first, then invert — pace tools handle this directly.
- Need distance or length conversions too? The unit converter on this site covers those.
A worked example, a mistake to avoid, and when not to use this tool
Say you are driving in the US and your rental car’s speedometer reads 60 mph, but a friend asks how fast that is in kilometers per hour. Enter 60, choose mph as the starting unit and km/h as the target, and you get 96.56064 km/h — about 96.6 km/h in everyday terms. The quick mental check is 1 mile is about 1.6 km, so 60 times 1.6 gives you roughly 96, which tells you the exact answer is in the right ballpark.
The mistake to watch for is treating pace and speed as the same thing. Pace is time per distance, like minutes per kilometer, while speed is distance per time, like km/h. If a training plan says 5 minutes per kilometer, you cannot type 5 into this converter and expect a useful speed — you need to work out the pace first, or use a pace tool. The other common slip is picking knots when you mean nautical miles: knots are already a speed, so a boat doing 10 knots is doing 10 nautical miles per hour, not 10 nautical miles.
Do not use this tool when what you really need is a finish time or a pace for a run. For that, the Pace Calculator is the right fit, because it works from distance and time. And if you need to convert a distance, a weight, or a temperature rather than a speed, use the Unit Converter instead. Converted speed limits are also guidance, not a calibrated speedometer reading, so always drive to the road conditions in front of you.