Driving Time Calculator
Enter the distance and a realistic average speed, and add rest stops if you are taking them. This gives the time the journey actually takes rather than the time the limit suggests.
Journey time
7h 46m
- Driving
- 6h 46m
- Stopped
- 1h
- Breaks
- 3
- Average over the whole journey
- 54 miles per hour
- Average speed, not the limit. Over a long journey the average is well below the limit once junctions, towns and traffic are counted — planning at the limit is how arrival times slip.
- A break at the destination is not a break, so the final stretch never earns one.
About journey time
Journey time is distance divided by speed, and the difficulty is entirely in the speed. People plan at the limit, and no long journey is ever completed at the limit.
Junctions, roadworks, towns at either end, traffic, and the simple fact that you cannot start and finish at speed all pull the average down. On a mixed route a realistic average is often ten to twenty per cent below the road's limit, and on a route with any town driving in it the gap is larger still.
Stops are the other half. A twenty minute break every two hours is a common rhythm on a long drive, and on a seven hour journey that is an hour that never appears in the plan. Fuel stops, food and the queue for it all sit on top of the driving.
The figure worth taking away is the door-to-door average, which is the total distance over the total elapsed time. It is usually startlingly lower than the number on the speedometer for most of the journey, and it is the only one that predicts an arrival time reliably.
What it works out
- Driving time from distance and average speed
- Rest stops counted separately
- The true door-to-door average speed
- Miles or kilometres
The formula
Driving = Distance ÷ Average speed Total = Driving + Breaks
420 miles at an average of 62 mph is 6.77 hours of driving — 6h 46m.
A break every two hours across 6.77 hours of driving means three stops, not four: the fourth would fall at the destination, and a break at the destination is not a break. Three twenty minute stops add an hour, so the journey takes 7h 46m in total.
That gives a door-to-door average of 54 mph against the 62 mph the car was doing while moving, and against the 70 the road is probably signed at. The gap between 70 and 54 is what turns a "six hour drive" into an eight hour day.
The average speed field is doing all the work here, and it is worth being pessimistic with it. Route planners are generally optimistic because they assume free-flowing traffic throughout, and any single delay costs more than a slightly higher cruising speed can recover.
- Average speed
- Over the whole route, including the slow parts at each end. Well below the limit on any real journey.
- Break every
- How long you drive between stops. Two hours is the usual advice on a long drive.
A worked example
A 420 mile drive averaging 62 mph, with a twenty minute break every two hours.
That works out to 7h 46m .
- Driving
- 6h 46m
- Stopped
- 1h
- Breaks
- 3
- Average over the whole journey
- 54 miles per hour
Questions
How long will my drive take?
Divide the distance by a realistic average speed, then add the stops. 420 miles at 62 mph is 6h 46m of driving, and 7h 46m with three twenty minute breaks.
What average speed should I use?
Below the limit, and further below it than feels right. On a mixed route ten to twenty per cent under the limit is realistic; with town driving at either end, more. Working backwards from a previous similar journey is the best guide.
Why is my average speed so much lower than my cruising speed?
Because the average includes everything that is not cruising — junctions, roundabouts, roadworks, towns and the slow start and finish. A journey cruising at 62 can easily average 54 door to door once stops are counted.
How often should I take a break on a long drive?
Every two hours is the standard advice, with at least fifteen minutes each time. Fatigue builds faster than most drivers notice, and the risk climbs sharply after about three hours without a stop.
Why does the tool give three breaks and not four?
Because the last stretch never earns one. Six and three quarter hours of driving splits into four intervals of under two hours, and the break that would follow the fourth falls at the destination.
Does driving faster save much time?
Less than it feels like, and it costs fuel sharply. Over 420 miles, raising the average from 62 to 70 mph saves about 46 minutes — but a single twenty minute delay gives most of that back, and the fuel penalty above 60 is steep.
Should I add time for fuel stops?
Yes, if they are not already in your break pattern. A fuel stop is rarely under ten minutes once you have queued, paid and rejoined the road.
Are route planner estimates accurate?
They are usually optimistic, because they assume traffic flows freely and they do not know your stops. Treat their figure as the driving time and add your own breaks to it.