Speed Distance Time Calculator
Calculate speed, distance, or time using the formula Speed = Distance / Time. Physics and travel calculator.
About this calculator
Choose what to find (speed, distance or time), enter the other two and get the answer with its formula. Works in km/h, m/s and mph.
A staple of school physics and everyday travel planning.
How to use it
- Choose to calculate speed, distance or time.
- Enter the two known values and pick the unit.
- Press Calculate.
The formulas
speed = distance ÷ time, distance = speed × time, time = distance ÷ speed. Convert units first: 1 m/s = 3.6 km/h; 1 mile = 1.609344 km; 1 mph = 1.609344 km/h. Average speed is total distance ÷ total time, not the average of speeds: driving 60 km at 30 km/h then 60 km at 60 km/h takes 2 h + 1 h = 3 h, so the average is 120 ÷ 3 = 40 km/h, not 45.
Worked example
120 km in 2 hours
| Speed | 120 ÷ 2 = 60 km/h |
| In m/s | 60 ÷ 3.6 = 16.67 m/s |
| Time at 80 km/h for 200 km | 200 ÷ 80 = 2.5 h = 2 h 30 min |
Tips and common mistakes
- Keep units consistent (km with hours, m with seconds).
- Convert minutes to hours by dividing by 60.
- Average speed uses total distance over total time.
- Multiply m/s by 3.6 for km/h.
- Add stops separately when planning trips.
Frequently asked questions
What is the speed formula?
Speed = distance ÷ time.
How do I convert m/s to km/h?
Multiply by 3.6.
How do I find time?
Distance ÷ speed.
What is average speed?
Total distance divided by total time.
How far in 2.5 hours at 60 km/h?
150 km.
Is it free?
Yes.