Speed is distance per unit time — kilometres per hour, miles per hour, metres per second, knots, or feet per second. Indian roads use km/h; US roads use mph; aviation and maritime use knots; physics uses m/s.
What is Speed Converter?
Speed conversion comes up when comparing car specs, reading aviation reports, calculating physics problems, or planning international road trips. Different fields default to different units, so a quick converter is useful.
Kilometres per hour (km/h) is the standard for road traffic in India and most of the world. Miles per hour (mph) is standard in the US, UK, and a few other former British colonies. Metres per second (m/s) is the SI scientific unit. Knots (nautical miles per hour) is used in aviation and shipping — 1 knot ≈ 1.852 km/h.
Conversions are fixed multiplicative factors with no offsets, so the math is straightforward.
Speed conversion factors
- Factor
- m/s per unit—the m/s equivalent of 1 of each unit
How to use this calculator
Pick source and target speed units, enter the value.
Enter speed value
Decimal-precise. Common values: 100 km/h (highway speed), 60 mph (US highway), 9.81 m/s² (gravity acceleration — note this is acceleration, not speed).
Pick units
km/h for road, mph for US/UK road, m/s for physics, knots for aviation/maritime.
When speed conversion matters
Comparing car specs
Imported cars list 0-60 mph time; Indian cars use 0-100 km/h. 60 mph = 96.6 km/h, so the times are not directly comparable.
Aircraft cruise speeds
Cruising speed is usually given in knots. A typical airliner cruises at 450-500 knots ≈ 833-925 km/h.
Physics homework
School problems use SI (m/s); the calculator handles km/h to m/s conversion (divide by 3.6).
Wind speed
Weather reports might use km/h, knots (marine), or mph. The calculator equates them all.
Common mistakes to avoid
Reading a US treadmill's speed as km/h
American treadmills default to mph. 'Speed 6' on a US machine is 9.7 km/h — a brisk run, not a gentle jog. Check the unit toggle before judging your fitness.
Using km/h numbers in physics formulas
Kinematics equations (v = u + at, etc.) need m/s. Divide km/h by 3.6 first: a car at 72 km/h is moving 20 m/s. Mixing units is the top cause of wrong physics answers.
Confusing knots with km/h in weather reports
Cyclone wind speeds come in knots from marine sources and km/h from IMD bulletins. 100 knots = 185 km/h — misreading the unit understates a storm by almost half.
Glossary
- km/h
- Kilometres per hour. Standard for road speed in India.
- mph
- Miles per hour. Standard in the US, UK.
- m/s
- Metres per second. SI scientific unit. Multiply by 3.6 to get km/h.
- Knot (kn)
- Nautical miles per hour. 1 knot = 1.852 km/h. Used for ships and aircraft.