Speed Converter
Convert between miles per hour, kilometres per hour, metres per second and knots instantly — with all four units shown side by side.
Result
How It Works
Speed is distance divided by time, and every speed unit is just a different pairing of the two. Miles per hour rules the roads in the US and UK; kilometres per hour is the standard almost everywhere else; metres per second is the unit of science and sprinting; and knots — one nautical mile per hour — are the standard at sea and in the air, because a nautical mile is tied to the Earth's geometry.
The conversion factors are exact by definition: 1 mph = 1.609344 km/h, 1 knot = 1.852 km/h, and 1 m/s = 3.6 km/h. To convert, the calculator first changes your value to km/h and then to the unit you want, so every result is consistent whichever direction you convert.
Worked examples: 60 mph = 96.5606 km/h = 26.8224 m/s = 52.1386 knots. 100 km/h = 62.1371 mph = 27.7778 m/s = 53.9957 knots.
How to Use This Converter
Enter a speed, pick the units, and the answer updates live — with all four units shown in the table underneath.
- Enter the speed — any non-negative number, including decimals.
- Pick the "From" and "To" units — mph, km/h, m/s or knots in either box.
- Read the result — the headline shows your chosen conversion, and the table shows the same speed in all four units at once.
The Reset button restores the example (60 mph to km/h) so you can start over.
Tips and Practical Advice
Speed conversions matter most when the stakes are real — speed limits, sailing and flight — so it is worth knowing the rough figures as well as the exact ones.
- Memorise the driving anchors. 30 mph ≈ 48 km/h, 60 mph ≈ 97 km/h and 70 mph ≈ 113 km/h — the UK motorway limit is 70 mph, about 113 km/h.
- Use the ×8/÷5 shortcut. To estimate km/h from mph, multiply by 8 and divide by 5: 60 × 8 / 5 = 96, close to the exact 96.5606.
- Do not mix knots with mph. A knot is about 15% faster than a mile per hour (1 knot = 1.1508 mph), so a 20-knot wind is 23 mph, not 20.
- Convert before comparing. Comparing a 100 km/h limit with a 60 mph speedometer reading is meaningless until both are in the same unit — 100 km/h is only 62.1371 mph.
Frequently Asked Questions
What is 60 mph in km/h?
96.5606 km/h. The exact factor is 1 mph = 1.609344 km/h, so 60 × 1.609344 = 96.56064.
What is a knot in mph?
One knot is 1.1508 mph. A knot is one nautical mile (1.852 km) per hour, so it is slightly faster than a statute mile per hour.
How many m/s is 100 km/h?
27.7778 m/s. Divide km/h by 3.6: 100 / 3.6 = 27.7778.
Why do ships and planes use knots?
Because a nautical mile is defined as one minute of latitude, which makes knots fit naturally with nautical charts and navigation.
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