Speed, Distance & Time Calculator
Enter any two of speed, distance, and time — the calculator solves for the third, with pace included.
How this calculator works
Speed, distance, and time are locked together by one relationship — distance = speed × time — so knowing any two fixes the third. Fill in the two you know, leave the third blank, and the calculator solves for the missing one. Results come back in both mph and km/h for speed, miles and kilometres for distance, hours-and-minutes for time, and minutes-per-mile pace for runners.
Worked examples
- Road trip: 60 miles in 1.5 hours → average speed 40 mph (64.4 km/h). Useful after the fact, too: it's your true average including every stop light.
- Journey planning: 250 miles at an expected 65 mph → about 3 hours 51 minutes of driving time, before breaks.
- Running: a 5K (3.11 miles) in 0.5 hours → 6.2 mph, which the pace line translates to about 9:39 per mile — the number most training plans speak in.
Getting useful answers
- Use decimal hours. 90 minutes is 1.5 hours; 20 minutes is 0.333. (Minutes ÷ 60 = decimal hours.)
- Average ≠ cruising speed. Real journeys average well below the speed you "drive at" because of stops and slowdowns — 10–20% below is typical for long car trips.
- Metric users: the tool's native units are miles and mph, but every result is mirrored in km and km/h; you can also enter kilometres as if they were miles and read all outputs in metric consistently.
Frequently asked questions
How do I enter a time like 1 hour 45 minutes?
Convert to decimal hours: divide the minutes by 60 and add. 1 h 45 m is 1.75; 2 h 20 m is 2.333. The results panel converts back to hours-and-minutes format for you.
Can I work fully in kilometres?
Yes — enter distances in km and read the km/h and km outputs, ignoring the mph/miles mirror. Because the relationship is proportional, the numbers stay internally consistent in whichever unit you type.
What is 'pace' and why do runners use it?
Pace is time per unit distance — minutes per mile here — the inverse of speed. Runners prefer it because race targets ('hold 9:00 miles') and split times are naturally expressed that way rather than in mph.