Formula
Time = Distance ÷ Average Speed The result is only as accurate as the average speed you enter. Using your top cruising speed instead of a realistic average — one that accounts for traffic, stops, fuel breaks, and slower stretches through towns or construction — will make the estimate run short. For a long road trip, using an average speed below your typical highway cruising speed can help account for stops, traffic, towns, construction, and other delays.
Worked examples
300 miles at an average of 60 mph takes exactly 5 hours. 250 kilometers at 100 km/h takes 2 hours 30 minutes. A messier case — 437 miles at 65 mph — comes out to 6 hours 43 minutes, illustrating why the calculator rounds to the nearest minute rather than leaving an unwieldy decimal.
Estimating arrival time
Adding a departure date and time calculates an estimated arrival by adding the travel duration directly to that departure moment. If your trip spans a Daylight Saving Time transition, the arrival time reflects the clock change. For example, a 3-hour trip departing at 1:00 AM just before the spring-forward transition can arrive at 5:00 AM: only 3 hours have elapsed, but the local clock advances by 4 hours because one hour is skipped.
Frequently asked questions
How do I calculate travel time from distance and speed?
Divide the distance by the average speed. 300 miles at an average of 60 mph takes 300 ÷ 60 = 5 hours. The result is only as reliable as the average speed used — a realistic average that accounts for stops and slower stretches, not just top cruising speed.
What average speed should I use for a road trip estimate?
Something below your typical highway cruising speed, to account for stops, traffic, and slower stretches through towns or construction zones. Using your top speed as the average will consistently underestimate the actual travel time.
Does this calculator account for Daylight Saving Time when estimating arrival?
Yes. The calculator treats the travel time as an elapsed duration and adds it to the departure moment. If a Daylight Saving Time transition occurs during the trip, the estimated arrival reflects the resulting local clock change without changing the actual travel duration.
Does this calculator account for destination time zones?
No. The calculator estimates elapsed travel time from distance and average speed. When you enter a departure date and time, the estimated arrival is displayed using your device's local time zone. If your trip crosses into another time zone, the local clock time at your destination may be different. Use a time zone converter to convert the estimated arrival to the destination's local time.