Speed Distance Time Calculator
Solve for speed, distance, or time from the other two, step by step. Enter time as hours or hh:mm:ss, and see the formula triangle that links them.
The speed, distance, and time relationship
Speed, distance, and time are linked by one formula: speed = distance ÷ time. Rearranging it lets you find any one of the three from the other two.
The three rearrangements
- Speed = distance ÷ time
- Distance = speed × time
- Time = distance ÷ speed
Worked examples
- Speed: 275 miles in 5 hours → 275 ÷ 5 = 55 mph.
- Distance: 55 mph for 3 hours → 55 × 3 = 165 miles.
- Time: 150 miles at 50 mph → 150 ÷ 50 = 3 hours.
Entering time as hh:mm:ss
You can type time as a decimal number of hours or as hours:minutes:seconds. For example 5:22:10 converts to 5 + 22/60 + 10/3600 ≈ 5.3694 hours before the formula is applied.
Keep the units consistent
The speed unit is set by the distance and time units. Miles with hours give miles per hour; kilometres with hours give km/h. Mixing units — minutes with hours, or metres with kilometres — is the most common error.
Common mistakes
- Mixing units for distance and time.
- Dividing the wrong way — speed is distance over time, not time over distance.
- Forgetting to convert minutes into a fraction of an hour.
For a per-unit rate rather than distance over time, use the unit rate calculator.
Frequently asked questions
- What is the speed distance time formula?
- Speed equals distance divided by time. Rearranged, distance equals speed times time, and time equals distance divided by speed. The three form a triangle with distance on top and speed and time below.
- How do you calculate speed?
- Divide the distance by the time. If you travel 275 miles in 5 hours, the speed is 275 divided by 5, which is 55 miles per hour.
- How do you calculate distance?
- Multiply the speed by the time. At 55 miles per hour for 3 hours you cover 55 times 3, which is 165 miles.
- How do you calculate time?
- Divide the distance by the speed. Covering 150 miles at 50 miles per hour takes 150 divided by 50, which is 3 hours.
- How do I enter time as hours, minutes, and seconds?
- Type it as hh:mm:ss, like 5:22:10 for 5 hours 22 minutes 10 seconds. The calculator converts it to a decimal number of hours, here about 5.3694 hours, before using the formula.
- Why do the units have to match?
- The speed unit comes from the distance and time units you use. Miles and hours give miles per hour; kilometres and hours give kilometres per hour. Mixing minutes with hours, or metres with kilometres, gives a wrong answer.
- What is the formula triangle trick?
- Draw a triangle with distance on top and speed and time in the two bottom corners. Cover the quantity you want — covering speed leaves distance over time, covering distance leaves speed times time, and covering time leaves distance over speed.