Speed Converter

Type a value in either box and pick the units. The other box updates instantly. Use the swap button to reverse the direction.

• All 6 units are supported in both directions.
• Results update live as you type — no button to press.
• Values are formatted for readability while staying precise.

Convert 100 km/h to meters per second. Since 100 km = 100,000 m and 1 hour = 3,600 s, 100,000 ÷ 3,600 = 27.78 m/s.

• In mph: 100 × 0.621371 = 62.14 mph
• In knots: 100 ÷ 1.852 = 53.99 knots
• In Mach: 27.78 ÷ 343 ≈ 0.081 at sea level

• m/s — the SI unit of speed, standard in science.
• km/h vs mph — road speeds; 1 mph = 1.609344 km/h.
• Knots — 1 nautical mile per hour (1.852 km/h), used in aviation and marine navigation.
• Mach — the ratio of speed to the speed of sound (343 m/s at sea level).

• NIST — SI Units
• Math is Fun — US Standard Speed