Speed Distance Time Calculator
Solve for speed, distance or time from the other two values, with flexible distance, time and speed units.
🔒 Runs entirely in your browser — nothing is uploadedThe speed, distance and time triangle
Speed, distance and time are tied together by one relationship that can be written three ways. The base form is distance = speed × time. Rearranged, it gives speed = distance ÷ time and time = distance ÷ speed. People often picture this as a triangle with distance on top and speed and time below: cover the value you want and the remaining two show whether to multiply or divide. This calculator does that rearrangement for you — choose the unknown and it applies the matching formula automatically.
Units are where these problems get tricky, so each field has its own unit menu. Distance can be metres, kilometres or miles; time can be seconds, minutes or hours; and speed can be km/h, m/s or mph. Internally the script converts distance to metres and time to seconds so the arithmetic is always consistent, then converts the answer into the output unit you selected. That means you can enter a distance in miles and a time in minutes and still read a clean answer in mph or km/h without doing any manual conversion yourself.
Everyday uses and accuracy
This tool is handy for trip planning, running and cycling pace, delivery estimates, physics homework and any situation where two of the three quantities are known. To estimate a drive, enter the distance and your average speed to get travel time. To check a workout, enter distance and time to get your average speed. Remember that real journeys include stops, traffic and changing speeds, so an average-speed result is a planning estimate rather than a guarantee. All values stay on your device — nothing is uploaded — and the calculation uses standard JavaScript precision, which is accurate for everyday distance, speed and time questions.
Worked examples
Driving 150 km at an average of 75 km/h takes 150 ÷ 75 = 2 hours. Running 10 km in 50 minutes is 0.2 km per minute, which is 12 km/h, or a pace of 5 minutes per kilometre. Cycling at 18 mph for 2.5 hours covers 18 × 2.5 = 45 miles.
The time field takes a single number with a unit, so enter 1 hour 30 minutes as 1.5 hours or as 90 minutes, not as 1.30. Useful reference points: 1 m/s equals 3.6 km/h, and 1 mph is about 1.609 km/h. If an answer looks implausible, check the unit menus first, since a kilometre-versus-mile or minute-versus-hour mix-up is the usual cause.
How to use
- Choose what to solveSelect speed, distance or time as the unknown you want the calculator to find.
- Enter the two known valuesFill in the other two fields and pick their units. Only the inputs you need stay editable.
- Read the answerThe result and the formula used update instantly in your chosen output unit.