Speed Calculator
Solve for speed, distance or time, in any combination of units.
Inputs
Result
66.6667
Speed (mph)
66.667
Speed (km/h)
107.290
Distance (m)
160,934.40
Time (s)
5,400.00
Step by step
Convert distance to metres
100 mi × 1609.344
= 160934.4 m
Convert time to seconds
1.5 hr × 3600
= 5400 s
Speed = distance ÷ time
160934.4 m ÷ 5400 s
= 29.8027 m/s = 66.6667 mph
How it works
Speed, distance and time are related by speed = distance ÷ time. Knowing any two lets you compute the third. This calculator works entirely in SI (metres and seconds) internally, then converts to your chosen output unit. Unit conversion tables are exact by definition (1 mile = 1609.344 m; 1 knot = 1852 m/hr).
Formulas
Speed
Speed = Distance ÷ Time
- v
- Speed
- d
- Distance
- t
- Time
Distance
Distance = Speed × Time
Time
Time = Distance ÷ Speed
Frequently Asked Questions
How do I convert 60 mph to km/h?
60 mph × 1.609344 = 96.56 km/h. Alternatively, enter speed=60, speedUnit=mph, solve for Distance over 1 hour and read the km result — but the unit converter is simpler for a pure conversion.
What is a knot?
A knot is 1 nautical mile per hour. One nautical mile = 1852 metres, defined as 1 arc-minute of latitude on the Earth's surface. It's the standard unit in aviation and marine navigation.
If I drive 100 miles at 65 mph, how long does it take?
Select 'Solve for Time', enter distance=100 miles, speed=65 mph. Result: 100/65 ≈ 1.538 hours = 1h 32m 18s.
Can this solve for average speed over a whole journey?
Yes — enter total distance and total time to get the average speed. Note that average speed is total distance / total time, not the arithmetic mean of the speeds at each segment.