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Speed Converter

Free online speed converter. Select any unit pair below or use the interactive converter.

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All conversions (enter a value above)

All Speed Conversion Pairs

Meter/Second (m/s) → Kilometer/Hour (km/h) Meter/Second (m/s) → Mile/Hour (mph) Meter/Second (m/s) → Foot/Second (ft/s) Meter/Second (m/s) → Knot (kn) Meter/Second (m/s) → Mach (Ma) Kilometer/Hour (km/h) → Meter/Second (m/s) Kilometer/Hour (km/h) → Mile/Hour (mph) Kilometer/Hour (km/h) → Foot/Second (ft/s) Kilometer/Hour (km/h) → Knot (kn) Kilometer/Hour (km/h) → Mach (Ma) Mile/Hour (mph) → Meter/Second (m/s) Mile/Hour (mph) → Kilometer/Hour (km/h) Mile/Hour (mph) → Foot/Second (ft/s) Mile/Hour (mph) → Knot (kn) Mile/Hour (mph) → Mach (Ma) Foot/Second (ft/s) → Meter/Second (m/s) Foot/Second (ft/s) → Kilometer/Hour (km/h) Foot/Second (ft/s) → Mile/Hour (mph) Foot/Second (ft/s) → Knot (kn) Foot/Second (ft/s) → Mach (Ma) Knot (kn) → Meter/Second (m/s) Knot (kn) → Kilometer/Hour (km/h) Knot (kn) → Mile/Hour (mph) Knot (kn) → Foot/Second (ft/s) Knot (kn) → Mach (Ma) Mach (Ma) → Meter/Second (m/s) Mach (Ma) → Kilometer/Hour (km/h) Mach (Ma) → Mile/Hour (mph) Mach (Ma) → Foot/Second (ft/s) Mach (Ma) → Knot (kn)

What is Speed and Why Do We Convert It?

Speed measures how fast an object moves — the distance covered per unit of time. It plays a critical role in transportation, aviation, maritime navigation, sports, and physics. The challenge is that different regions and industries use different speed units: most of the world uses kilometers per hour (km/h), the United States and UK use miles per hour (mph), science uses meters per second (m/s), aviation and maritime use knots, and aeronautics references Mach number. Accurate speed conversion is essential for safe travel, engineering, and sports analysis.

Speed Unit Conversion Formulas

Quick reference for the most commonly used speed conversions:

1 kilometer/hour (km/h) = 0.277778 m/s
1 mile/hour (mph) = 1.60934 km/h = 0.44704 m/s
1 meter/second (m/s) = 3.6 km/h = 2.23694 mph
1 knot (kt) = 1.852 km/h = 1.15078 mph
1 foot/second (ft/s) = 0.3048 m/s = 1.09728 km/h
Mach 1 ≈ 343 m/s ≈ 1,235 km/h (at sea level, 20°C)

Common Speed Conversions — Reference Chart

FromToMultiply By
km/hmph0.621371
mphkm/h1.60934
m/skm/h3.6
km/hm/s0.277778
knotkm/h1.852
knotmph1.15078
mphm/s0.44704
ft/skm/h1.09728

Real World Examples of Speed Conversion

Speed Units Explained

UnitSymbolUsed In
Kilometer per Hourkm/hRoad transport, weather (most countries)
Mile per HourmphRoad transport (US, UK)
Meter per Secondm/sPhysics, science, SI standard
Knotkt or knAviation, maritime, weather
Foot per Secondft/sUS engineering, ballistics
MachMaAerospace, supersonic speeds

Frequently Asked Questions

How do I convert km/h to mph?

Multiply by 0.621371. For example, 120 km/h = 120 × 0.621371 = 74.56 mph. Or divide by 1.60934.

How do I convert mph to km/h?

Multiply by 1.60934. For example, 60 mph = 60 × 1.60934 = 96.56 km/h.

What is a knot in km/h?

1 knot = 1.852 km/h. A knot is defined as 1 nautical mile per hour. It is the standard speed unit used in aviation and maritime navigation worldwide.

What is Mach 1 in km/h?

Mach 1 (speed of sound) ≈ 1,235 km/h = 767 mph at sea level at 20°C. The actual value varies with air temperature and altitude — at high altitude, where air is colder, sound travels slower.

How do I convert m/s to km/h?

Multiply by 3.6. For example, 10 m/s = 10 × 3.6 = 36 km/h. This is the most common conversion in physics problems.

What is the fastest speed ever recorded?

The Parker Solar Probe reached approximately 692,000 km/h (430,000 mph) — the fastest human-made object ever. By comparison, light travels at 1,079,252,848 km/h (299,792,458 m/s).