Average speed is the main assumption
Use a realistic average speed, not the posted speed limit.
Example
A trip that covers 300 miles at an average of 60 mph takes 5 hours of driving. Adding 30 planned stop minutes makes the total about 5 hours and 30 minutes.
Common mistakes
Do not use a short highway speed if the route includes city traffic, mountain roads, ferry waits, border checks, fuel stops or charging stops. For longer drives, include rest breaks separately so the estimate reflects the time you actually need.
Limitations
This calculator does not know your route, traffic, weather, road closures, time zones or legal rest requirements. Use it as a planning estimate, then check a live map or travel service before departure.
Last reviewed: 2026-05-17