Speed, Distance and Time Calculator

Speed, distance and time are tied together by one formula, so knowing two gives you the third. This calculator solves for whichever you need, in any mix of units, from a physics problem to working out how long a trip will take.

How to Use It

1. Choose what to Find: Speed, Distance or Time.
2. Enter the other two values and pick each one’s unit.
3. Choose the unit for the answer in Answer In.
4. Press Calculate. A time answer is also written as hours, minutes and seconds.

How It Works

Average speed is distance divided by time:

Rearranged, $d = vt$ and $t = \frac{d}{v}$. The calculator converts every value to meters and seconds first, so you can mix units such as miles and minutes.

Worked Example

A train covers 150 km in 2.5 hours:

How long does a 5 km run take at 4 m/s? $t = \frac{5000 \text{ m}}{4 \text{ m/s}} = 1250 \text{ s}$, which is 20 minutes 50 seconds.

Tips and Common Mistakes

• This is average speed. Stops and slowdowns are included in the total time.
• Convert minutes properly. 1 hour 30 minutes is 1.5 hours, not 1.3.
• km/h to m/s: divide by 3.6. And m/s to km/h: multiply by 3.6.
• Speed isn’t velocity. Velocity includes direction; for a round trip, average velocity is 0 even though average speed isn’t.
• Keep an eye on the units of the answer. Pick them in Answer In rather than converting by hand.