Speed / distance / time calculator
Solve for speed, distance or time when you know two of the three values. Useful for road trips, running pace, freight planning and physics work.
Last updated: May 2026
Fill in any two values to calculate the third.
Speed, distance and time: practical use cases
Fill in any two fields and the calculator derives the third. The most common use is estimating trip time: enter your expected average speed and the route distance, and you get the travel time in hours. Note that average speed for a road trip is always lower than your cruising speed — a 500 km route at 120 km/h on the motorway still averages around 90 km/h when you include service stops and urban sections.
The calculator works with any consistent unit pair. If you enter speed in mph and distance in miles, the result is in hours. Time is always decimal: 1.5 means one and a half hours, not one hour fifty minutes.
Speed, distance and time examples
| Speed | Distance | Time | Activity |
|---|---|---|---|
| 5 km/h | 10 km | 2 h 0 min | Hiking pace |
| 15 km/h | 20 km | 1 h 20 min | Cycling average |
| 50 km/h | 100 km | 2 h 0 min | Urban driving |
| 90 km/h | 100 km | 1 h 7 min | Rural road driving |
| 120 km/h | 300 km | 2 h 30 min | Motorway trip |
| 850 km/h | 1,000 km | 1 h 11 min | Commercial flight |
Frequently Asked Questions
How do I calculate average speed for a road trip?
Divide total distance by total elapsed time — including stops, not just driving time. If you drive 400 km and the door-to-door time is 5 hours (including a 45-minute break), your average speed is 400 ÷ 5 = 80 km/h. Highway cruising speed is irrelevant to this figure.
What does 0.5 hours mean in this calculator?
30 minutes. The time field uses decimal hours: 1.25 = 1 hour 15 minutes, 1.75 = 1 hour 45 minutes, 2.5 = 2 hours 30 minutes. The calculator does not accept hours:minutes format. To convert minutes to decimal hours, divide by 60.
How far can I drive in 2 hours at motorway speeds?
At 120 km/h for exactly 2 hours: 240 km. Enter 120 in speed and 2 in time, leave distance blank. For a realistic road trip estimate, use a lower average speed — 90–100 km/h is more typical for a mixed motorway and regional road journey including brief stops.