Speed = distance ÷ time. Drive 150 miles in 2.5 hours and your average speed is 60 mph; run 10 km in 50 minutes and it is 12 km/h. Enter distance and time in matching units. To convert, 1 mph = 1.609344 km/h = 0.44704 m/s, and 1 knot = 1.852 km/h.
This speed calculator finds average speed from distance and time with speed = distance ÷ time. Keep units consistent so the answer is meaningful. Defaults of distance 100 and time 2 return speed 50.
Drivers, runners, and physics students use it for quick pace checks. For straight line length between coordinates, use the distance calculator.
Speed unit conversions (NIST)
| Unit | m/s | km/h | mph |
|---|---|---|---|
| 1 mph | 0.44704 | 1.609344 | 1 |
| 1 km/h | 0.2777778 | 1 | 0.6213712 |
| 1 knot | 0.5144444 | 1.852 | 1.1507794 |
| 1 m/s | 1 | 3.6 | 2.2369363 |
Note: 60 mph = 96.56 km/h; 100 km/h = 62.14 mph. Source: NIST SP 811 Appendix B.9.
Pace to speed
| Pace | Speed |
|---|---|
| 6:00 min/mile | 10 mph |
| 8:00 min/mile | 7.5 mph |
| 10:00 min/mile | 6 mph |
| 5:00 min/km | 12 km/h |
| 6:00 min/km | 10 km/h |
Rule: speed = 60 ÷ pace in minutes. For full pace math, use the pace calculator.
How the formula works
Dividing how far you traveled by how long it took yields average speed for that trip. Larger distance at the same time raises speed. Longer time at the same distance lowers speed. This is average speed, not peak speed.
Worked example
Distance 100, time 2. Speed = 100 ÷ 2 = 50 (same unit system you chose).
| Input | Value |
|---|---|
| Distance | 100 |
| Time | 2 |
| Speed | 50 |
How to use the fields
- Distance is the path length in your chosen length unit.
- Time is the duration in the matching time unit.
Unit pairs that stay clear
Miles with hours give miles per hour. Kilometers with hours give km/h. Meters with seconds give m/s, but this calculator still labels the answer km/h or mph, so read the number as m/s (multiply by 3.6 for km/h). Convert first if your stopwatch and map markers disagree on units.
Speed, Distance and Time Formulas
The three formulas come from one relationship. Cover the value you want in the speed-distance-time triangle (distance on top, speed and time below):
| To find | Formula | Worked example |
|---|---|---|
| Speed | speed = distance ÷ time | 10 km in 50 minutes: 10 ÷ (50 ÷ 60) = 12 km/h |
| Distance | distance = speed × time | 65 mph for 3.5 hours: 65 × 3.5 = 227.5 miles |
| Time | time = distance ÷ speed | 300 km at 80 km/h: 300 ÷ 80 = 3.75 h = 3 h 45 min |
Entering minutes: the time field is in hours, so divide minutes by 60. 150 km in 2 h 30 min is time 2.5, speed 150 ÷ 2.5 = 60 km/h. For 50 minutes enter 0.8333.
| Minutes | Enter as hours |
|---|---|
| 5 min | 0.0833 (rounded) |
| 10 min | 0.1667 (rounded) |
| 15 min | 0.25 |
| 20 min | 0.3333 (rounded) |
| 30 min | 0.5 |
| 40 min | 0.6667 (rounded) |
| 45 min | 0.75 |
| 50 min | 0.8333 (rounded) |
| 75 min | 1.25 |
| 90 min | 1.5 |
Common mistakes
- Mixing minutes and hours without converting
- Using map straight line distance when the trip followed a longer road
- Entering zero time
- Comparing speeds computed in different unit systems
Trip planning uses
Estimate arrival by rearranging to time = distance ÷ speed when you know a realistic average speed for the route type. Highway averages differ from city averages. Using an optimistic speed makes every arrival estimate early and stressful.
To estimate what the trip costs, use the fuel cost calculator.
Include planned stops in total time if you care about door to door average. Excluding stops reports moving average speed instead, which is a different question.
Limitations
Results ignore acceleration profiles, traffic rules, and elevation. They answer one question: distance divided by time for the numbers you provide.
The tool only solves for speed. For time = distance ÷ speed or distance = speed × time, rearrange or use the distance calculator. For time math, use the time calculator, and to convert other units, the unit converter.