Speed / Distance / Time
Enter any two values and leave the third blank — it will be calculated automatically.
Fill in any two — the third is worked out for you.
About the Speed / Distance / Time
The speed, distance and time calculator solves for any one of the three variables when you know the other two. Enter any two values and the third is calculated.
How to use the Speed / Distance / Time
Frequently Asked Questions
Speed, Distance and Time Explained
Speed, distance and time are related by three simple formulas. This calculator solves for whichever value you don't know given the other two.
The formulas
- Speed = Distance ÷ Time
- Distance = Speed × Time
- Time = Distance ÷ Speed
Common uses
- Road trips: How long will it take to drive 300 miles at 60 mph?
- Running: If I run at 10 km/h for 45 minutes, how far will I go?
- Cycling: What average speed do I need to cycle 100 miles in 6 hours?
- Physics homework: Solve SDT problems with any two of the three values
Unit consistency
Always use consistent units. If speed is in km/h, distance must be in km and time in hours. If time is in minutes, convert to hours first (divide by 60) before using the formulas.
Common speeds compared
Everyday speeds across mph, km/h and m/s — handy for sanity-checking a result.
| Activity | mph | km/h | m/s |
|---|---|---|---|
| Walking | 3 mph | 4.8 km/h | 1.3 m/s |
| Jogging | 6 mph | 9.7 km/h | 2.7 m/s |
| Cycling | 15 mph | 24.1 km/h | 6.7 m/s |
| City driving | 30 mph | 48.3 km/h | 13.4 m/s |
| Motorway | 70 mph | 112.7 km/h | 31.3 m/s |
Worked examples
Real questions this calculator answers, with the maths shown.
| Question | Working | Answer |
|---|---|---|
| Drive 300 miles at 60 mph? | 300 ÷ 60 | 5 hours |
| Run at 10 km/h for 45 min? | 10 × 0.75 | 7.5 km |
| Cycle 100 miles in 6 hours? | 100 ÷ 6 | 16.7 mph |
| Fly 500 km in 1 hour? | 500 ÷ 1 | 500 km/h |
Speed unit conversions
How one unit of each speed compares across mph, km/h, m/s and knots.
| From | mph | km/h | m/s | knots |
|---|---|---|---|---|
| 1 mph | 1 | 1.609 | 0.447 | 0.869 |
| 1 km/h | 0.621 | 1 | 0.278 | 0.54 |
| 1 m/s | 2.237 | 3.6 | 1 | 1.944 |
| 1 knots | 1.151 | 1.852 | 0.514 | 1 |