The fuel policy attached to a car hire booking is easy to skim past when comparing prices, but it can move the real cost of your rental by a meaningful amount if you get it wrong. There are really only a handful of policy types in circulation, one of them is consistently the best value for almost everyone, and at least one is specifically structured to profit from drivers who don't return the car exactly as instructed. Here's how each works and which to choose.
Full-to-full: the one to look for
Full-to-full means you collect the car with a full tank and return it full, refuelling yourself at a station of your choice shortly before drop-off. This is, for the overwhelming majority of rentals, the best-value policy available, because you only ever pay standard pump prices for exactly the fuel you use — nothing more, nothing prepaid, nothing wasted. If a rental offers a choice of fuel policy, full-to-full is almost always worth actively selecting over the alternatives, even if another option looks marginally cheaper on the headline price.
The only real catch with full-to-full is logistics: you need to find a fuel station near the drop-off point, and returning the car anything less than genuinely full — even by a small margin — usually triggers a refuelling charge from the rental company at a rate well above the pump price you'd have paid yourself. Plan your route so the last fuel stop is close to the return location, and keep the receipt in case of a dispute over the tank level.
Full-to-empty (prepaid fuel): the trap
Under a full-to-empty or prepaid fuel policy, you pay for a full tank of fuel upfront at the time of booking or collection, and you're not required — and often not able — to get any refund for fuel remaining in the tank when you return the car, even if you return it nearly full. This policy is priced to assume you will use most or all of a tank, which is rarely how a real trip works out, particularly for anything less than a genuinely long drive that empties the tank close to return. Most travellers who choose or are defaulted into this option end up paying for meaningfully more fuel than they actually use, which is exactly the outcome the policy is designed around.
Prepaid fuel is almost never worth it unless you are certain the car will come back close to empty — a genuinely long one-way drive with no return leg, for instance. For a typical multi-day rental with return driving, city stops and a mix of use, you will very likely pay for fuel you never burn. Decline this option by default and switch to full-to-full if it's offered as an alternative.
Same-to-same: a smaller-scale version of full-to-full
Some companies offer a same-to-same policy — return the car with the same fuel level it had at collection, whatever that level was, rather than requiring a full tank both ways. This works similarly to full-to-full in principle but starts from whatever level the car happens to have rather than a guaranteed full tank, which can be an awkward starting point to match precisely. Where offered as an alternative to full-to-full, it's a reasonable second choice, though full-to-full remains simpler to execute accurately since "full" is an unambiguous target in a way that an arbitrary starting fraction isn't.
Empty-to-empty: rare, and rarely useful
A small number of rentals, mostly commercial or very short-term city bookings, use an empty-to-empty policy — collect with whatever fuel is left, return with the tank close to empty. This is uncommon for standard leisure rentals and generally not something you'll be choosing between on a typical booking, but if it does appear as an option, treat it with the same caution as full-to-empty: read exactly how "empty" is defined and measured before assuming it favours you.
Comparing the options
| Policy | How it works | Verdict |
|---|---|---|
| Full-to-full | Collect full, return full, pay pump price for what you use | Best value for almost everyone — actively choose this if offered |
| Full-to-empty (prepaid) | Pay for a full tank upfront, no refund for what's left | Usually a worse deal — avoid unless certain to return near-empty |
| Same-to-same | Return at the same level as collection | Reasonable alternative to full-to-full, slightly fiddlier to match exactly |
| Empty-to-empty | Collect and return with minimal fuel | Uncommon; check the exact terms if it appears |
The refuelling charge if you get it wrong
Whichever policy applies, returning a car under a full-to-full or same-to-same agreement without the required fuel level triggers a refuelling charge from the rental company — and this rate is consistently well above what you'd pay filling up yourself at a nearby station. It typically covers both the missing fuel and a service or handling fee on top, calculated in a way that makes it clearly worth refuelling yourself before returning the car rather than accepting the company's rate, even if the nearest station is slightly out of your way.
Electric and hybrid vehicles: a different set of rules
For an electric hire car, the "fuel" policy is really a charge-level policy, and the same principle broadly applies — collect and return at the agreed charge level, usually full or a set percentage, and expect a charging fee well above typical public charging rates if you return with less. Locating a charging point near the drop-off, and allowing enough time to actually charge before returning the car, matters more for an EV than finding a petrol station does for a conventional car, since charging generally takes longer than refuelling. Confirm the exact policy and expected charge level when booking an electric vehicle rather than assuming it mirrors a standard fuel policy exactly.
How to avoid the trap when booking
- Check the fuel policy explicitly before completing a booking — it's often shown as a small line in the rate details rather than prominently on the search results page.
- If full-to-full isn't the default and a cheaper prepaid alternative is shown instead, check whether you can switch to full-to-full, even for a small additional charge — it's usually still the better overall deal.
- Plan your last day's route to pass a fuel station near the return location, so returning with a genuinely full tank is straightforward rather than a last-minute scramble.
- Keep the fuel receipt from your final fill-up until the return inspection is complete, in case of any dispute about the tank level.
This sits alongside the other pre-collection checks covered in our guide to renting a car abroad for the first time, which walks through the booking and collection process more broadly, and is worth reading together with our guide to car hire insurance and, if you're paying with a debit card, hiring a car with a debit card — the fuel policy is just one line of several worth checking before you sign anything at the car hire desk.
Frequently asked questions
Which fuel policy is the best value for a typical rental?
Full-to-full, in almost every case — you collect and return the car with a full tank and pay standard pump prices for only the fuel you actually use, with no prepayment and no wasted fuel.
Is prepaid fuel ever worth choosing?
Rarely — only if you're certain the car will return close to empty, such as a genuinely long one-way drive with no return leg. For most rentals involving a mix of driving, prepaid fuel means paying for more fuel than you use.
What happens if I return the car without a full tank under a full-to-full policy?
The rental company will charge a refuelling fee, typically well above the pump price, to cover both the missing fuel and a handling charge. Refuelling yourself near the return point before drop-off avoids this.
Do electric hire cars have a similar policy?
Yes, in principle — an agreed charge level at collection and return, usually full or a set percentage, with a charging fee above typical public rates if you return with less. Confirm the exact terms and allow enough time to charge before returning the car.
Sources and further reading:
- Fuel policy definitions and terms: individual rental company websites (Hertz, Avis, Budget, Europcar, Enterprise).
- General rental terminology and consumer guidance: BVRLA (British Vehicle Rental and Leasing Association).
- Related: Renting a car abroad for the first time and car hire insurance explained on Viamo.