Calculator Suite
Speed & Velocity Converter
Convert between mph, km/h, m/s, knots and other speed units
Popular Speed & Velocity Converter Conversions
Quick Presets
Base Unit Method
= Value in target unit
= Value in input unit
= Conversion factor to base
= Conversion factor from base
Category-Specific Formula
Speed vs Velocity
Speed is how fast (scalar), velocity includes direction (vector). In everyday use, they're often interchangeable.
Transportation Units
Cars use mph/km/h, aircraft and ships use knots, scientists use m/s.
Maritime and Aviation
Knots relate to latitude navigation. 1 nautical mile = 1 minute of latitude.
Physics/Engineering
Meters per second (m/s) is the SI unit for speed in physics calculations.
Quick reference: 1 mph ≈ 1.61 km/h, 1 knot ≈ 1.85 km/h, 1 m/s = 3.6 km/h. Highway speed: 65 mph = 105 km/h. Speed of sound: 343 m/s ≈ 767 mph.
Select Units
Choose "From" (e.g., MPH) and "To" (e.g., KM/H).
Enter Speed
Type the velocity to convert.
View Result
Get the converted speed instantly.
🚗 Example: US to European Speed Limit
65 mph = 104.6 km/h = 56.5 knots
Assumes:
- • Constant velocity
- • Standard unit definitions
- • Ground-relative speed
Does NOT include:
- • Relativistic effects
- • Wind/current adjustments
- • Acceleration calculations
MPH vs KPH?
1 MPH = 1.609 km/h. Quick: multiply mph by 1.6. US uses mph, most countries use km/h.
What is a knot?
1 knot = 1 nautical mile/hour = 1.852 km/h = 1.151 mph. Used in aviation and maritime.
What is the speed of sound?
Mach 1 ≈ 343 m/s = 767 mph = 1235 km/h at sea level, 20°C. Varies with temperature.
How fast is 100 km/h in mph?
100 km/h = 62.14 mph. Common European highway speed limit.
Why do ships use knots?
Knots relate directly to navigation. 1 nautical mile = 1 minute of latitude on Earth.