Last Updated on November 1, 2023 by Chris


You get to the rental car company and need to decide: Should you prepay for gas in a rental car?

You never want to pay more than you have to for a rental car—and that includes gasoline. The agent at the rental car companies will likely try to sell you on their prepaid gas program. That’s where you get charged for a tank of gas at a cheaper-than-average per-gallon price. Sounds like a good deal, right?

Of course, there’s a catch.

Why Prepaying for Gas is a Car Rental Rip-Off

Here are six reasons to think twice about prepaying for that tank:

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You have to return a completely empty tank. When you prepay for the gas, you’re paying for the full tank. If you bring it back a quarter full or even 90 percent full, there’s no refund for the gas you left in the tank. If you don’t use every last drop, you’re paying for gas you didn’t use. Bringing it back with more than fumes is a higher average price per gallon for you.

Unfortunately, it’s not uncommon to be erroneously slapped with an automatic fuel-service charge even when you properly refill the tank. That’s because “connected car” sensors are notoriously fickle, and often read the tank as being shy a gallon or two even when they have been filled to the brim. We always recommend taking a photo with your cell phone of the dashboard, showing both the mileage and fuel level as you return the car. Also, take a photo of the fuel receipt from your pre-return fillup. Being armed with these proofs is your best protection against getting overcharged.

The tax man wants his share. Every state, county, city, and airport has staked their claim over rental car revenue, and gas is no exception. If you buy the prepaid gas, that 10-cent-per-gallon “cheaper than pump price” rate can get inflated by 50 cents per gallon or more—just from rental taxes. The price you see at the pump includes all taxes but the prepaid fuel they’re selling you as a “deal” usually does not. Of course, they won’t tell you that little tidbit. Suddenly, it doesn’t look like such a good deal.

Prepaid prices don’t include credit card rewards. Some credit cards, like the Costco Anywhere Card by Citi, offer a very generous bonus on fuel fill-ups, be it a nice 5-percent rebate at the pump or double or triple points when filling up. If you buy the gas from the rental company, you won’t earn those bonus rewards.

Don’t trust and verify.

Gas might be cheaper where you’re dropping off. If you’re doing a one-way rental, be sure to check gas prices in your drop-off area. Prepaid gas prices are based on wherever you pick up the car, so don’t overpay if you’re picking up in an expensive gas locale.

You have to trust them on the tank size. Tank sizes vary—sometimes even within a given make and model. When the delivery truck rolls in with a load of new cars, the fleet manager loads all the information about that car into the computer—often quickly, and sometimes making assumptions about the car’s specifications. If they are lazy or make a mistake, you can be overcharged for extra gallons if you prepay.

The “pump price” might be a lie. That sign on the rental counter showing current local gas prices might be out of date. Or it might have used the closest gas station to the airport (which rarely has a competitive price, for obvious reasons), or the station with the highest prices in the area. It’s rarely the cheapest gas available, especially if you have a warehouse club membership. Instead, check GasBuddy for a true comparison.

When Prepaying for Gas Makes Sense

If you’re the kind of person who dashes for the airport at the very last minute, or you know you’ll be rushing right from a meeting to your flight, then prepaying for gas is often a better deal than risking that you can’t refill the tank before you return the car. In that case, the rental car company will fill the tank at a punitive rate (which can sometimes be $10 per gallon), even if you’re only three or four gallons short of a full tank.

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Rental car sales agents are highly incentivized to sell you on the benefits of prepaying for gas. Convenience comes at a price, and unless you return the car literally on fumes, you’re likely throwing a significant sum down the drain. Budget in an extra 10 or 15 minutes to fill up your car and pocket those extra dollars.