Find the Distance
Distance is speed multiplied by time: S = v · t. Enter speed and time in any units — we convert to SI and show the substitution.
Solution
The one formula of motion. All three problems are the same formula S = v · t turned different ways: distance is speed times time, speed is distance over time, time is distance over speed. The classic trap is units: with kilometers and minutes mixed together, convert everything to one system first. The calculator does that for you and shows how.
FAQ
How do you convert km/h to m/s?
Divide by 3.6. A kilometer is 1000 meters and an hour is 3600 seconds, so km/h · 1000/3600 = km/h / 3.6. For example, 72 km/h = 20 m/s. To go back, multiply by 3.6.
Why convert units to one system?
The formula S = v · t only works with consistent units: speed in m/s and time in seconds give meters. Plugging km/h together with minutes produces nonsense. The safest route is SI: meters and seconds.
How do you remember what divides by what?
The classic triangle: S on top, v and t below. Cover the unknown — what remains shows the formula: cover S and you see v · t; cover v and you see S over t, i.e. S / t.
What is average speed and what is the catch?
Average speed is the whole distance divided by the whole time — not the arithmetic mean of speeds. Drive half the route at 60 km/h and half at 40 km/h, and the average is 48, not 50: the slow half takes longer.
Free motion-problem calculator: finds speed, time, or distance from the two known values and shows the full solution — the formula, the SI unit conversion, and the substitution.
Any units work: kilometers or meters, hours, minutes or seconds, km/h or m/s. The calculator converts everything to one system and shows exactly how: 72 km/h = 72 · 1000 / 3600 = 20 m/s. The answer comes in convenient units.
Everything runs in the browser with no data sent anywhere. Useful for school physics and math motion problems, and for quick real-life estimates of travel time or average speed.