Speed Calculator
- Updated
- Formula shown
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Results
Speed = 6 mph (3 mi in 30 min)
How to use the speed calculator
- Choose what to find: speed, distance, time, or pace.
- Enter the two values you know. Time goes in hours, minutes and seconds; leave a box empty or at 0 if you don't need it, and values over 59 are fine (90 minutes works).
- Pick the units for each value and for the answer. Speed results also show the matching pace per kilometer and per mile.
- In pace mode, convert a pace into a speed (or the other way round) and see finish times for common race distances.
Speed, distance and time formulas
d = v × t
t = d ÷ v
pace = t ÷ d = 1 ÷ v
Speed (v) is distance (d) divided by the time (t) taken. This is average speed: it tells you nothing about stops or changes of pace along the way. Pace is the same relationship turned upside down, time per unit of distance, which is why runners talk about "five-minute kilometers". The calculator converts every input to meters and seconds before dividing, using exact definitions: 1 mile = 1,609.344 m, 1 nautical mile = 1,852 m (so 1 knot is 1.852 km/h), 1 foot = 0.3048 m and 1 km/h = 1 ÷ 3.6 m/s.
Worked examples
- A 10 km run in 50 minutes: 10 ÷ (50 ÷ 60) = 12 km/h (7.46 mph). The pace is 5:00 per km, or 8:03 per mile.
- A 300 km drive at an average of 100 km/h: 300 ÷ 100 = 3 hours, shown as 3:00:00.
- Driving at 60 mph for 2 hours 30 minutes: 60 × 2.5 = 150 miles.
Speed conversion table
| km/h | mph | m/s | knots | ft/s |
|---|---|---|---|---|
| 5 | 3.11 | 1.39 | 2.7 | 4.56 |
| 10 | 6.21 | 2.78 | 5.4 | 9.11 |
| 20 | 12.43 | 5.56 | 10.8 | 18.23 |
| 30 | 18.64 | 8.33 | 16.2 | 27.34 |
| 50 | 31.07 | 13.89 | 27 | 45.57 |
| 80 | 49.71 | 22.22 | 43.2 | 72.91 |
| 100 | 62.14 | 27.78 | 54 | 91.13 |
| 120 | 74.56 | 33.33 | 64.79 | 109.36 |
Pace chart
Each row is the same effort expressed four ways, with the finish time it gives for 10 km and a marathon (42.195 km), computed with the calculator's engine.
| Per km | Per mile | km/h | mph | 10K | Marathon |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 15 | 9.32 | 40:00 | 2:48:47 |
| 4:30 | 7:15 | 13.33 | 8.28 | 45:00 | 3:09:53 |
| 5:00 | 8:03 | 12 | 7.46 | 50:00 | 3:30:59 |
| 5:30 | 8:51 | 10.91 | 6.78 | 55:00 | 3:52:04 |
| 6:00 | 9:39 | 10 | 6.21 | 1:00:00 | 4:13:10 |
| 7:00 | 11:16 | 8.57 | 5.33 | 1:10:00 | 4:55:22 |
| 8:00 | 12:52 | 7.5 | 4.66 | 1:20:00 | 5:37:34 |
Speed, velocity and average speed
In physics, speed is how fast something moves, while velocity also includes the direction. A car driving once around a 1 km circuit in one minute has an average speed of 60 km/h but an average velocity of zero, because it ends where it started. This calculator works with speed. It also gives the average over the whole trip: a journey with traffic lights and a stretch of highway can average 50 km/h even though the speedometer rarely showed exactly that. For a constant speed, average and instantaneous speed are the same, and the three formulas above describe the motion completely.
Tips and common mistakes
- Convert minutes properly. 1 hour 30 minutes is 1.5 hours, not 1.3. Entering hours, minutes and seconds in separate boxes avoids this.
- Average speed over two legs is total distance divided by total time, not the average of the two speeds. Going 60 km at 30 km/h and returning at 60 km/h averages 40 km/h.
- Knots are for boats and aircraft. A knot is one nautical mile per hour, about 15% faster than one mile per hour.
- Pace and speed move in opposite directions: a lower pace number means a higher speed.
For distances between two points on a map, try the distance calculator; for the time between two clock times, the time duration calculator.
Frequently asked questions
How do you calculate speed?
Divide the distance by the time taken: v = d ÷ t. Running 10 km in 50 minutes is 10 ÷ (50 ÷ 60) = 12 km/h, which is about 7.46 mph.
How do I work out travel time from distance and speed?
Divide the distance by the speed: t = d ÷ v. A 300 km drive at an average of 100 km/h takes 3 hours. Multiply the decimal part of an hour by 60 to get minutes.
How do I convert pace to speed?
Divide 60 by the pace in minutes. A pace of 5:00 per km is 60 ÷ 5 = 12 km/h, and 8:00 per mile is 60 ÷ 8 = 7.5 mph. A 5:00 per km pace is the same as about 8:03 per mile.
How do I convert km/h to mph?
Divide km/h by 1.609344, because a mile is exactly 1,609.344 meters. 100 km/h is about 62.14 mph, and 65 mph is about 104.6 km/h. To get m/s, divide km/h by 3.6.
What is a knot?
A knot is one nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 knot is 1.852 km/h or about 1.151 mph. Knots are used for ships, aircraft and wind speed.