Complete guide
Speed calculator: solve speed, distance or time
Choose speed, distance or time as the unknown. Calculator24 converts the entered units through meters and seconds, solves the relationship and shows equivalent speeds, distance and elapsed time.
The speed-distance-time triangle
Average speed is total distance divided by total elapsed time. Rearranging the same equation solves distance or time.
Three formulas
Use compatible units or let the engine convert them.
v=d/td=vtt=d/vWorked road-trip example
A 100 km trip completed in 2 h averages 50 km/h. Converting the same physical speed gives about 31.07 mph.
Unit conversion
The engine uses meters and seconds internally. One international mile is exactly 1,609.344 m and one nautical mile is exactly 1,852 m.
Average versus instantaneous speed
A trip average includes every faster and slower segment covered by the elapsed-time input. A speedometer reports an approximate instantaneous value.
Speed versus velocity
Speed has magnitude only. Velocity also includes direction, so turning or returning to the start changes velocity even when distance and speed are positive.
Common exact or defined conversions
| Relationship | Value |
|---|---|
| 1 km/h | 0.277777… m/s |
| 1 mph | 0.44704 m/s |
| 1 knot | 1.852 km/h |
| 1 m/s | 3.6 km/h |
Frequently asked questions
How do I calculate speed?
Divide distance by elapsed time.
How do I calculate distance?
Multiply speed by time.
How do I calculate travel time?
Divide distance by speed.
Does average speed include stops?
Yes if the entered elapsed time includes them.
Is speed the same as velocity?
No; velocity includes direction.
Can I mix miles and minutes?
Yes. Choose each input unit independently.
What to keep in mind
This is scalar average speed. It does not model direction, acceleration, stops hidden from elapsed time, route distance, traffic or measurement error.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.