Speed Distance Time Calculator
Solve speed = distance ÷ time for any of the three, with hours-minutes-seconds input, km/h, mph or m/s output, running pace per km and per mile, and the steps shown.
Speed Distance Time Calculator: with the default inputs, average speed is 80 km/h.
Not used when solving for distance.
Time taken. Not used when solving for time.
Not used when solving for speed.
- Solved for
- speed = 80 km/h = 49.71 mph
- Distance
- 100 km
- Time
- 1 hour, 15 minutes
- Pace per kilometer (min:sec)
- 0:45
- Pace per mile (min:sec)
- 1:12
Assumptions
- Speed is the average over the whole distance.
- 1 mile = 1,609.344 m and 1 nautical mile = 1,852 m exactly.
- Pace is rounded to the nearest second.
| Speed(km/h) | Time | Versus your speed |
|---|---|---|
| 48 km/h | 2 hours, 5 minutes | costs 50 minutes, 0 seconds |
| 64 km/h | 1 hour, 33 minutes | costs 18 minutes, 45 seconds |
| 72 km/h | 1 hour, 23 minutes | costs 8 minutes, 20 seconds |
| 80 km/h | 1 hour, 15 minutes | your speed |
| 88 km/h | 1 hour, 8 minutes | saves 6 minutes, 49 seconds |
| 100 km/h | 1 hour, 0 seconds | saves 15 minutes, 0 seconds |
| 120 km/h | 50 minutes, 0 seconds | saves 25 minutes, 0 seconds |
| 160 km/h | 37 minutes, 30 seconds | saves 37 minutes, 30 seconds |
Each row keeps the distance fixed and changes only the speed. Notice how the rows above your speed save less and less: halving the journey time takes twice the speed, not a bit more of it.
How this is worked out
The formula
speed = distance ÷ time distance = speed × time time = distance ÷ speed Conversions: 1 m/s = 3.6 km/h = 2.23694 mph = 1.94384 knots Pace (min per km) = 60 ÷ speed (km/h)
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Solve for
- Choose one of 3 options.Speed — from distance & time · Distance — from speed & time · Time — from distance & speed
- Distance
- Not used when solving for distance.in km, mi, m, ft, yd, nmi · 0 or more · defaults to 100
- Hours
- Time taken. Not used when solving for time.0 or more · whole numbers only · defaults to 1
- Minutes
- A number.from 0 to 59 · whole numbers only · defaults to 15
- Seconds
- A number.from 0 to 59.999 · defaults to 0
- Speed
- Not used when solving for speed.in km/h · 0 or more · defaults to 60
What you get back
- Average speedmain answer
- Solved for
- Distance
- Time
- Pace per kilometer (min:sec)
- Pace per mile (min:sec)
What this assumes
- Speed is the average over the whole distance.
- 1 mile = 1,609.344 m and 1 nautical mile = 1,852 m exactly.
- Pace is rounded to the nearest second.
About this calculator
Speed, distance and time are locked together by one relation — v = d ÷ t — so knowing any two gives the third. Pick which one you want, enter the other two in whatever units suit the problem (miles and mph, meters and seconds, nautical miles and knots), and the calculator returns the answer with the conversions made explicit. Time is entered as hours, minutes and seconds so "1 h 15 min" doesn't have to become 1.25 in your head.
Average speed, not instantaneous
Distance divided by total time is average speed. A 100 km drive that takes 1 h 15 min averaged 80 km/h even if the speedometer showed 110 on the highway and 0 at the lights. It also means you cannot "make up" a slow first half: cover the first half of a trip at 40 km/h and you would need infinite speed on the second half to average 80, because the time budget is already spent. The average of two speeds over equal distances is the harmonic mean, not the arithmetic one.
Pace
Runners, cyclists and swimmers think in minutes per unit distance rather than distance per hour. The calculator shows pace per kilometer and per mile alongside the speed; 10 km/h is 6:00 per km and 9:39 per mile. Marathon pacing: 4 hours for 42.195 km is 5:41 per km.
Reading the results
- Average speed can be switched between m/s, km/h, mph, ft/s and knots.
- Time is shown as hours, minutes and seconds; the steps show the raw seconds.
- Use Solve for to answer questions such as "how fast must I run the last 5 km to finish under 50 minutes?" by targeting the time output.
Common mistakes
- Decimal minutes: 1.30 hours is 1 h 18 min, not 1 h 30 min. Entering h/m/s separately avoids this.
- Mixing units: 100 miles at 60 km/h is not 1 h 40 min. The calculator converts everything to meters and seconds first.
- Applying the formula to accelerating motion and expecting the instantaneous speed. With constant acceleration use the kinematic equations (see the free-fall and projectile calculators).
Frequently asked questions
▸What is the formula for speed?
Speed = distance ÷ time. Rearranged: distance = speed × time, and time = distance ÷ speed. The triangle mnemonic puts distance on top over speed and time.
▸How do I calculate average speed for a trip with two legs?
Add the total distance and divide by the total time — don't average the two speeds. 60 km at 60 km/h plus 60 km at 30 km/h takes 3 hours for 120 km: 40 km/h, not 45.
▸How do I convert km/h to m/s?
Divide by 3.6. 90 km/h = 25 m/s. For mph to m/s multiply by 0.44704; for knots multiply by 0.5144.
▸How do I convert speed to running pace?
Pace in minutes per km = 60 ÷ speed in km/h; per mile = 60 ÷ speed in mph. 12 km/h is 5:00 per km. The calculator shows both paces automatically.
▸Why can't I average two speeds to get the average speed?
Because you spend more time at the slower speed. Average speed weights each speed by the time spent at it, which is why the correct average over equal distances is the harmonic mean.
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