Speed Calculator
Speed20.00
Distance100.00
Time5.00
This speed calculator solves the relationship speed = distance ÷ time for whichever quantity you leave blank. Enter any two of speed, distance, and time, and it returns the third. Because the three variables are linked by a single equation, the tool works equally well for finding average speed, the distance covered, or the time a journey takes, all in consistent units of your choice.
Formula
speed = distance ÷ time (so distance = speed × time, time = distance ÷ speed)
- speed
- Average speed (distance unit per time unit)
- distance
- Distance travelled, in your chosen length unit
- time
- Time elapsed, in your chosen time unit
How it works
- Choose what you want to find with the mode switch: Find Speed, Find Distance, or Find Time.
- Enter the two values you know. The units are yours to set (for example km and hours, or miles and hours) as long as you keep them consistent.
- The calculator applies the matching rearrangement of speed = distance ÷ time and displays all three values, highlighting the one you solved for.
Worked examples
A car travels 100 miles in 5 hours; find the average speed.
- Use speed = distance ÷ time.
- speed = 100 ÷ 5 = 20.
Average speed = 20 (miles per hour).
Travelling at 60 mph for 2.5 hours; find the distance.
- Use distance = speed × time.
- distance = 60 × 2.5 = 150.
Distance = 150 miles.
Frequently asked questions
- What is the basic speed formula?
- Speed equals distance divided by time. Rearranging the same relationship gives distance = speed × time and time = distance ÷ speed, which is exactly what this calculator does depending on the mode you pick.
- Does this give average or instantaneous speed?
- It gives average speed over the whole trip, because it divides total distance by total time. Instantaneous speed at a single moment requires calculus and is not what this tool computes.
- What units should I use?
- Any units work as long as distance and time are consistent. If you enter miles and hours, the speed is in miles per hour; kilometres and hours give km/h. The calculator does not convert units for you.
- How is this different from a pace calculator?
- Speed expresses distance per unit time (such as mph), while pace expresses time per unit distance (such as minutes per mile). They describe the same motion inverted, and runners often prefer pace.