🧮 Calculators & Daily Life

Speed, Distance & Time

Given any two of speed, time and distance, calculate the third.

Examples (click to try)

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How to Use the Speed, Distance & Time Calculator

Fill in two of speed, time and distance, then press Calculate to find the missing one. Clicking an example chip fills the values and calculates automatically. Tick "Use miles (mph / mi)" and the input fields themselves switch to mph and miles: anything already typed in is converted for you, so the answer does not change. Time stays in hours either way.

Worked examples

  • 120 km at 60 km/h → time 2.00 h (distance ÷ speed)
  • 10 km in 1 h → speed 10.0 km/h (distance ÷ time)
  • 80 km/h × 2.5 h → distance 200.0 km (speed × time)
  • 20 km on foot at 4 km/h → time 5.00 h (walking / hiking estimate)
  • Time set to 0 while solving for speed → shows "Values must be greater than zero." (no Infinity)

Common Uses

  • Estimating travel time from distance and average speed.
  • Checking average speed after a drive, ride, walk or delivery route.
  • Finding distance covered when you know speed and elapsed time.

Assumptions and Units

The calculator uses distance = speed × time and treats the entered speed as a constant average over the whole interval. Stops, acceleration, traffic, gradients, and wind are not modelled. Entering 60 km/h for two hours therefore means an average of 60 km/h, regardless of the speed at individual moments.

The miles option uses the international mile, 1 mile = 1.609344 km, for both input and output; entered values are shown rounded to four significant digits when the toggle is flipped, and flipping it straight back restores the figure you started from. Convert minutes or seconds to hours before entering them. For min/km or min/mi pacing and race-distance projections, use the Running Pace Calculator.

FAQ

Is my data sent to a server?
No. Everything runs in your browser; nothing is transmitted or stored externally.
Which of the three can it solve?
Enter any two of speed, time and distance and the missing one is computed. A blank speed gives distance ÷ time, a blank time gives distance ÷ speed, a blank distance gives speed × time.
Units?
Metric by default: speed in km/h, distance in km, time in hours. Ticking “Use miles” switches the input fields as well as the result to mph and miles, and converts whatever you have already entered. Time is always in hours.
What happens if I enter 0?
Zero and negative values are guarded, so no Infinity or NaN appears. Asking for speed with time set to 0, for example, shows "Values must be greater than zero."
What happens if I fill in all three fields?
It shows "Enter exactly two values." and does not calculate. This is not a checker that verifies whether three entered values agree with the formula, so leave the field you want to solve for empty.
For a round trip at two different speeds, is the average just the mean of the two?
No. For two legs of equal distance the average speed is the harmonic mean. Driving 30 km out at 60 km/h and back at 40 km/h takes 0.5 h plus 0.75 h, so 60 km in 1.25 h gives 48 km/h, not the 50 km/h you get by averaging the speeds. The gap widens as the two speeds diverge, so compute each leg separately, add the times, then work out the overall average.