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Speed Converter

Convert speed units — kilometres per hour, miles per hour, metres per second, knots, and feet per second — for vehicles, aviation, sport, and physics.

Enter your values

Result

100 Kilometres / hour =
62.137169 Miles / hour
Quick answer

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

Formula
Result = Value × Source factor / Target factor (factors relative to m/s)
Factor
m/s per unit—the m/s equivalent of 1 of each unit
Worked example
Value100
Fromkm/h
Tomph
1 km/h = 0.277778 m/s
1 mph = 0.44704 m/s
100 × 0.277778 / 0.44704
➜ 100 km/h = 62.14 mph

How to use this calculator

Pick source and target speed units, enter the value.

  1. 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).

  2. 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.

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.
Disclaimer: Results are estimates based on the inputs you provide. They are not professional advice. For consequential decisions — financial, tax, medical, or legal — verify with a qualified professional.

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