Speed Distance Time Calculator
Find Any Value ⚡
Enter any two values and the third is calculated instantly. The formula triangle makes it easy — cover the value you want to find.
Leave the value you want to find blank
Quick Examples
Speed Distance Time Formulas
Speed = Distance ÷ Time
Distance = Speed × Time
Time = Distance ÷ Speed
Use the triangle — cover the value you want to find, and the remaining two show the calculation. If they are side by side, multiply. If one is above the other, divide.
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Frequently Asked Questions
What units should I use?
Speed, distance, and time units must be compatible. If speed is in mph and distance in miles, time will be in hours. This calculator handles unit conversions automatically for the combinations available.
How do I convert minutes to hours?
Divide by 60. For example, 90 minutes = 1.5 hours. Enter 1.5 in the time field with "hours" selected, or enter 90 with "minutes" selected.
What is average speed?
Average speed is total distance divided by total time. It does not account for changes in speed during the journey — it gives a single representative value for the whole trip.
Why is this called the SDT triangle?
The formula triangle is a teaching aid used in GCSE science and maths. Writing S, D, T in a triangle (D on top, S and T on the bottom) lets you cover the unknown and read off the formula directly.