Towing Fuel Cost Calculator
The extra fuel comes from the van's weight and its drag
No single figure fits every trip, because your speed, the terrain and the wind all change it.
Enter the fuel consumption you get without the van and this estimates the extra litres and dollars per 1,000km.
1. Your car, without the van
We do not hold fuel figures for individual vehicles, so we never guess yours.Use the number off your own dash or your last few fills.
2. What you are towing
Pick a range to prefill its ATM (aggregate trailer mass), or type the ATM off the van's compliance plate.
ATM is on the compliance plate. The estimate uses it because the car hauls the loaded van, not the empty one. See our plate guide.
3. Price and distance
We do not publish a fuel price, because the one that matters is the one you pay.
Towing this rig
Enter what your car uses without the van, and the van's ATM, and the estimate appears here.
A theoretical estimate
This tool works out the physical effort of towing and converts it to litres.The same van behind two different cars will not use the same fuel, so the arithmetic starts from the figure you give us.Treat the result as a planning figure and check it against your own fills.
How we work this out
Two forces do the extra work when you hitch up. The van's tyres resist rolling, in proportion to its weight. The van also pushes air aside, in proportion to its frontal shape and the square of your speed. Add the two and multiply by distance to get energy. Divide that by the energy in a litre of fuel, and by the share that reaches the wheels.
Every assumption it uses
- Rolling resistance coefficient of 0.01, sealed road.
- Air density of 1.2 kg per cubic metre.
- A steady 90km/h. Faster than that and drag climbs sharply, so the estimate reads low.
- 30% of the fuel's energy reaching the wheels.
- 38.6 megajoules per litre of diesel, 34.2 for petrol.
- Extra drag area by shape: full-height tourer 1.9 square metres, pop top or hybrid 1.2 square metres, small or teardrop 0.7 square metres.
- Your own consumption without the van, which already carries your car's weight, gearing and drag.
- A band of plus or minus 20% around the result.
This does not allow for hills, headwinds, roof racks or stop-start driving. Each of those increases what you use.
Air resistance costs more than weight at highway speed
At 90km/h, pushing air aside costs more than hauling the mass for most full-height vans. Two vans of the same weight can cost different amounts to tow. A lower travelling roof line saves fuel at highway speed.
Fuel is one line of the yearly bill. The rest is in our guide to what a caravan costs to run.
Towing fuel questions, answered
How much extra fuel does towing a caravan use?
It depends on the van's weight and how much air it pushes, so there is no single figure. Your speed, the terrain and the wind move it too. Your engine has to overcome the van's rolling resistance and its extra drag, and that extra work is what burns the fuel. This calculator turns those two forces into litres, starting from the consumption figure you get when you are not towing. The result is an estimate. Your own trip figures will differ from it.
Why does the calculator ask for my own fuel consumption?
Because every rig burns fuel differently. The same van behind two different cars will not use the same fuel, so a published figure for your car would be a guess. We ask for the figure you already know from your own driving, and do the arithmetic on that.
What does towing add to a trip?
It reports the extra litres and extra dollars per 1,000km, at the fuel price you actually pay. It also totals a trip distance you enter. The page lists every assumption behind the estimate.