Speed, Distance and Time Calculator
Know two of speed, distance and time? Get the third in any units, plus your pace, split times and when you'll arrive.
Type hours:minutes:seconds, like 0:50:00 for 50 minutes or 2:30 for 2½ hours.
Minutes, or h:mm. Added to the moving time for the total trip.
Shows when you'll arrive.
Fill in any two of distance, time and speed for each leg. Times are h:mm:ss, so 1:30 means 1 hour 30 minutes.
Split times and race predictions
0 = even pace. 1–3% is a typical negative split. A minus number means a slower second half.
If you race other distances at the same effort
| Race | Predicted time | Pace per km | Pace per mile |
|---|
Uses Pete Riegel's formula (time × (new distance ÷ old distance)1.06). It assumes you've trained for the longer race, so treat marathon predictions from short races as a best case.
The same result in every unit
| Speed and pace | Distance | Time |
|---|
How your answer is worked out
Speed = distance ÷ time. Turn it round for the other two.
- 1
Match the units
10 km0:50:00 = 0.8333 h
- 2
Pick the rule
speed =distance ÷ time
- 3
Your answer
10 ÷ 0.8333= 12 km/h
- 4
Pace and other units
5:00 per km= 7.46 mph
Read more: the formula, worked examples, pace, splits and averages
Speed, distance and time are tied together by one rule: distance = speed × time. Know any two and you can find the third. The only trick is keeping the units matched: kilometres with km/h and hours, miles with mph and hours, metres with m/s and seconds.
The formula
speed = distance ÷ time
distance = speed × time
time = distance ÷ speed
pace = time ÷ distance (minutes per km, mile, 100 m…)
average speed = total distance ÷ total time
Worked example
You run 10 km in 0:50:00. Fifty minutes is 50 ÷ 60 = 0.8333 hours, so your speed is 10 ÷ 0.8333 = 12 km/h. In miles per hour that is 12 ÷ 1.609344 = 7.46 mph. Your pace is 50 minutes ÷ 10 km = 5:00 per km, or 5:00 × 1.609344 = 8:03 per mile.
More examples
- Distance: driving at 100 km/h for 2 h 30 min covers 100 × 2.5 = 250 km.
- Time: a marathon (42.195 km) at 5:00 per km takes 42.195 × 5 = 210.975 minutes = 3:30:59.
- Stops and arrival: 300 km at 100 km/h is 3 hours of driving. Add 30 minutes of stops and leave at 22:30, and you arrive at 02:00 the next day. Your overall speed with stops is 300 ÷ 3.5 = 85.7 km/h.
Average speed over several legs
Don't just average the speeds. Drive 60 km at 60 km/h (1 hour) and then 60 km at 30 km/h (2 hours): you've done 120 km in 3 hours, so your average is 40 km/h, not (60 + 30) ÷ 2 = 45 km/h. The slow leg takes longer, so it counts for more. Advanced mode has a Several legs option that does this for you.
Pace, splits and race predictions
Runners, swimmers and rowers think in pace: time per km, per mile, per 100 m or per 500 m. Pick a pace unit in the speed box to type or see pace instead of speed. In Advanced mode you also get split times: a 10 km run in 50:00 is 5:00 every km at even pace. With a 2% negative split (second half 2% quicker), the first 5 km take 3000 ÷ 1.98 = 1515.2 s (25:15) and the second 24:45, so about 5:03 per km then 4:57 per km.
Race predictions use Pete Riegel's formula, new time = old time × (new distance ÷ old distance)1.06. A 20:00 5K predicts a 10K of 20 × 21.06 = 41.70 minutes, about 41:42.
Unit conversions used
| Unit | Equals |
|---|---|
| 1 mile | 1.609344 km (exact) |
| 1 nautical mile | 1.852 km (exact) |
| 1 foot / 1 yard | 0.3048 m / 0.9144 m (exact) |
| 1 m/s | 3.6 km/h |
| 1 mph | 1.609344 km/h |
| 1 knot | 1 nautical mile an hour = 1.852 km/h |
| 1 ft/s | 1.09728 km/h |
| Half marathon / marathon | 21.0975 km / 42.195 km |
Results assume a steady speed (or the average speed) over the whole distance. Real trips vary with traffic, hills, wind and fatigue, so add a margin for anything time-critical.
Common questions
What is the formula for speed, distance and time?
Speed is distance divided by time, distance is speed times time, and time is distance divided by speed. Enter any two and the calculator finds the third, in km, miles, metres, nautical miles, feet or yards, and km/h, mph, m/s, knots or ft/s.
How do I calculate average speed?
Divide the total distance by the total time, rather than averaging the speeds. Driving 60 km at 60 km/h and then 60 km at 30 km/h is 120 km in 3 hours, an average of 40 km/h, not 45. The Several legs option in Advanced does this for you.
How do I work out my running pace?
Pace is time divided by distance. A 10 km run in 50 minutes is 5:00 per km, or 8:03 per mile, which is a speed of 12 km/h. Pick a pace unit in the speed box to type or see pace instead of speed.
How long does it take to drive 250 km at 100 km/h?
Time is distance divided by speed, so 250 ÷ 100 = 2.5 hours, or 2 hours 30 minutes. Add your stops and departure time in Advanced to see when you will arrive. Real trips vary with traffic, hills and weather, so add a margin.
How do I predict a race time?
The calculator uses Pete Riegel's formula: new time = old time × (new distance ÷ old distance) to the power 1.06. A 20:00 5K predicts a 10K of 20 × 2 to the power 1.06 = 41.70 minutes, or about 41:42.
How do I convert knots to km/h?
One knot is one nautical mile an hour, which is 1.852 km/h. One mph is 1.609344 km/h and 1 m/s is 3.6 km/h. Choose any of these units on the speed box and the result converts as you type. Pace units work the same way.
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