🚗 Speed, Distance & Time Calculator
Enter any two of speed, distance and time, and the calculator works out the third.
Travel time
5h 0m
5 hours
The identity is distance = average speed × time. Give any two and the third follows: time = distance ÷ speed, speed = distance ÷ time. Keep units consistent (km with km/h, or miles with mph). This uses steady average speed, so real journeys with stops and traffic take longer. 🔒 In your browser.
How the speed, distance & time calculator works
Travel maths rests on one identity: distance = average speed × time. Rearranged, time = distance ÷ speed and speed = distance ÷ time. Pick which quantity to solve for, enter the other two, and the tool returns the answer — travel time is also shown in hours and minutes. Keep the units consistent (kilometres with km/h, or miles with mph); the toggle sets both together.
This assumes a constant average speed, so real journeys — with traffic, stops, junctions and speed limits — usually take longer than the ideal time. For a rough road-trip estimate, use a realistic average well below your top cruising speed, and add time for breaks.
Frequently asked questions
How do I calculate travel time?
Divide the distance by your average speed: time = distance ÷ speed. 300 km at 60 km/h takes 5 hours. The calculator also breaks the answer into hours and minutes.
How do I calculate average speed?
Divide the distance by the time taken: speed = distance ÷ time. Covering 150 miles in 3 hours is an average of 50 mph. Note this is average speed, including any slow sections, not your top speed.
How do I calculate distance from speed and time?
Multiply them: distance = speed × time. Two hours at 80 km/h covers 160 km. Make sure the speed and time units match (km/h with hours, mph with hours).
Why does my real journey take longer?
The formula uses a steady average speed, but real trips include acceleration, braking, traffic, junctions, rest stops and varying limits. Use a conservative average speed and add buffer time for a realistic arrival estimate.
What units should I use?
Keep them consistent: kilometres with km/h, or miles with mph, and time in hours (use decimals — 1.5 for an hour and a half). The km/mi toggle sets the distance and speed units together so they always match.