What is the formula for speed?

Speed = Distance ÷ Time. The three related formulas are: Speed = Distance / Time, Distance = Speed × Time, Time = Distance / Speed.

Does this work for any units?

Yes — as long as your units are consistent. If you enter distance in miles and time in hours, your speed is in mph. If distance is in km and time in hours, speed is km/h. The calculator doesn't convert units — keep them consistent.

What is average speed vs instantaneous speed?

Average speed is total distance divided by total time — it's what this calculator computes. Instantaneous speed is speed at a single moment, like what a car's speedometer shows. For uniform motion they're the same; for changing speeds only average speed can be computed from distance and time alone.

How do I convert km/h to mph?

Multiply by 0.621371. So 100 km/h = 62.1 mph. For mph to km/h, multiply by 1.60934.

Science

● Science

Speed calculator

Solve for speed, distance, or time. Enter two known values — the third is calculated instantly.

Distance (km / mi / m)

Time (hours)

Speed

km/h (or same unit/h)

Formula:

Speed = Distance ÷ Time

Distance = Speed × Time

Time = Distance ÷ Speed

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