Speed Calculator
Turn a distance and a time into speed, shown in mph, km/h, m/s, and knots.
This calculator works out how fast something moved by dividing the distance it covered by the time it took. Enter a distance, pick miles, kilometres, or metres, then type the time in hours. The speed appears at once in four units, and it all runs in your browser with nothing sent anywhere.
The formula
Speed is distance divided by time:
Speed = distance ÷ time
The tool first converts your distance to miles, divides by the time in hours to get miles per hour, then derives the rest: km/h = mph × 1.60934, m/s = km/h ÷ 3.6, and knots = mph ÷ 1.15078. For example, 100 miles in 1.5 hours gives 100 ÷ 1.5 ≈ 66.7 mph, which is about 107.3 km/h, 29.8 m/s, and 57.9 knots.
Using it and reading the result
The time field is measured in hours, so enter part-hours as decimals: 30 minutes is 0.5, and 90 minutes is 1.5. If you choose kilometres or metres for the distance, the conversion to miles happens behind the scenes before the speed is worked out, so the four unit boxes always agree with each other.
What it does and does not tell you
The number you get is an average speed across the whole distance and time you entered, not the speed at any single moment. A car that stops at lights and then races between them can share the same average as one holding a steady pace. For a meaningful answer the time must be greater than zero.
Frequently Asked Questions
Can I enter the time in minutes?
The field is in hours, so convert minutes to a decimal first: 15 minutes is 0.25, 30 minutes is 0.5, and 45 minutes is 0.75.
Is this average speed or instant speed?
It is the average speed over the distance and time you type. It cannot show how the pace changed during the trip.
Which distance units are supported?
Miles, kilometres, and metres. Whichever you pick, the result is still shown in mph, km/h, m/s, and knots.
Does this calculator store my data?
No. Everything runs in your browser and nothing is uploaded or saved.