Full to full or full to empty: which rental car fuel policy should you choose?

Fuel is the extra cost that surprises people most quietly. You do not notice it at the desk, but it shows up on the final bill as a refuelling charge or a tank you paid for and never used. The fuel policy in your contract decides which of the two can happen to you.

The three common fuel policies

ECC-Net describes full to empty bluntly: no refunds are paid for unused fuel, even if the whole tank was paid up front. ECC Malta calls it the least convenient option. With full to full, ECC-Net says you get a full tank and must return it full with the correct fuel type, or you pay for refuelling.

The Austrian ECC wrote in June 2026 that full to full is in most cases the fairest and cheapest option for consumers, and that other policies often lead to high refuelling fees or inflated fuel prices.

Why fuel was part of an EU action

In 2017 the EU's consumer protection authorities obtained commitments from five large rental companies. One of the points was clearer tank refuelling options, next to clearer prices, insurance and fairer damage handling. The European Commission's overview of that action still describes these commitments.

Prepaid fuel: only if it was clear

ECC-Net states that fuel should not be prepaid unless you were clearly notified of this in the contract you agreed to. If you booked full to full and the desk adds a prepaid tank, ask for it to be removed before you sign. Our article on extra insurance at the desk explains how to read each line of the contract.

1Check the fuel level against the form

ECC Malta advises making sure the representative records the fuel level correctly on the vehicle form. A tank recorded as full while the gauge shows seven eighths can cost you a refuelling charge at return. Start the car, look at the gauge, and photograph the dashboard together with the mileage.

2Check the fuel type

Wrong fuel is expensive and often excluded from damage waivers. ECC Malta notes that the fuel type is often shown on the inside of the fuel flap. Look before you leave, and photograph it if the car is unfamiliar to you.

3Find the price per litre and the service fee

ECC France notes that refuelling by the company costs more per litre and includes a service fee, and that this is lawful only if the fuel price is displayed at the company. Ask for the price if you cannot find it in the terms. Then you know what a missing quarter tank would cost.

4Plan the refuel before return

With full to full, find a station close to the return location. Keep the receipt: ECC France and the Austrian ECC both advise keeping your fuel receipt as evidence. Take a photo of the gauge at return, ideally together with the receipt and the mileage.

Which policy fits which trip?

Whatever you choose, read the fuel clause before you sign. The Austrian ECC warned in 2026 that policies other than full to full often come with high refuelling fees. The difference between the policies is rarely visible in the headline price of the booking.

Wrong fuel: an expensive mistake that is often not covered

Putting petrol in a diesel car, or the other way round, can damage the engine. Which? found in 2024 that some desk waivers did not cover misfuelling. That means the full cost may come to you even if you bought extra cover. If you put in the wrong fuel, do not start the engine. Call the company's assistance number and follow its instructions, and keep a record of the call.

A quick fuel checklist for the whole trip

1. At booking: note the fuel policy in the confirmation.
2. At the desk: check that the contract shows the same policy and no prepaid tank you did not ask for.
3. At the car: compare the gauge with the form, check the fuel type and photograph the dashboard.
4. Before return: refuel close to the return location and keep the receipt.
5. At return: photograph the gauge and the mileage, and ask for the level to be written on the return form.

What if the policy was changed at the desk?

Sometimes the booking says full to full, but the contract at the desk says something else. Compare the two before you sign. If you only notice afterwards, keep your booking confirmation and complain in writing. The terms check helps you find the fuel clause in your contract.

A refuelling charge on your bill

If you are charged for fuel after the trip, compare the charge with your receipt, your gauge photo and the price list. Our guide on refuelling charges after return explains how to object, and our letter templates give you a basic letter to start from.