What is my real cost per gallon with a rewards card?
About 8 to 20 cents under the sign. On a $4.00 gallon a flat 2% card is 8 cents, a 3% gas card 12, a 5% card 20. The card is the last layer: a station program and a cashback app come off first, and the percentage comes off what is left. Stacked, a $4.00 pump can beat a $3.85 sign.
The order matters
1. Station programCents off at the pump. Shell Fuel Rewards 3 to 10, BP earnify 5, Exxon Mobil Rewards+ 3 to 7, Circle K 5.
2. Cashback appAn Upside offer claimed before you pump, typically 15 cents, sometimes 5 to 25.
3. The cardIts percentage comes off what is left after 1 and 2.
One exception: paying with the GasBuddy card replaces your credit card, so its 3 cents and your card's percentage do not stack.
What each layer takes off a $4.00 gallon
| Layer | Off per gallon | On a 13 gallon fill |
|---|---|---|
| Flat 2% card (Citi Double Cash and the like) | 8¢ | $1.04 |
| 3% gas card (BofA Customized Cash, Blue Cash Preferred) | 12¢ | $1.56 |
| Costco Anywhere Visa, 4% on gas (5% at Costco) | 16¢ | $2.08 |
| 5% on gas (PayPal Debit with Fuel picked, Sam's Club Mastercard) | 20¢ | $2.60 |
| Upside offer, typical | 15¢ | $1.95 |
| Station program, base tier (Shell Gold, BP earnify) | 5¢ | $0.65 |
| Station program, top tier (Shell Platinum, 12 fills a quarter) | 10¢ | $1.30 |
Issuer gas rates, October 2026. A percentage is worth more when gas is expensive: the same 3% card is 9.6 cents at $3.20 and 15 at $5.00.
Two stations, worked through
| Step | Shell, $4.00 sign | Across the street, $3.85 sign |
|---|---|---|
| Station program | Gold, −5¢ | none |
| Upside offer | −15¢ | none |
| Before the card | $3.80 | $3.85 |
| 3% gas card | −11¢ | −12¢ |
| Real cost per gallon | $3.69 | $3.73 |
The pricier sign wins by 4 cents a gallon, 52 cents a fill. Swap the program and the offer to the cheap station and it wins by 34. The stack settles it, not the sign.
When the card is not enough
- You would use the same card at both. Then it cancels out. Only the program, the app and the drive decide.
- The card has a cap. Most 5% cards stop at $500 a quarter, then pay 1%.
- Warehouse gas needs a membership. Costco's $65 a year is 12 cents a gallon on 520 gallons. Take it off the saving.
Questions people ask
What is my real cost per gallon with a rewards card?
About 8 to 20 cents a gallon under the sign. On a $4.00 gallon a flat 2% card takes off 8 cents, a 3% gas card 12, a 4% card 16, a 5% category card 20. The card is the last layer, applied after any station program or cashback app, so stacking those first takes another 3 to 25 cents off before the percentage is counted.
How much does a 3% gas card save per gallon?
12 cents on a $4.00 gallon, about $1.56 on a 13 gallon fill. Because it is a percentage, it is worth more when gas is expensive and less when it is cheap: 9.6 cents at $3.20, 15 cents at $5.00.
Do rewards cards stack with Upside and station programs?
Yes. A station program (Shell Fuel Rewards, BP earnify, Exxon Mobil Rewards+) takes cents off at the pump. An Upside offer claimed before pumping takes off a typical 15 cents more, though Upside can pay less when a station reward is stacked. The card's percentage comes off what is left. The one exception is paying with the GasBuddy card, which replaces your credit card, so its 3 cents and the card's percentage do not stack.
Is a rewards card enough to beat a cheaper sign across the street?
Often not on its own. A 3% card is 12 cents on a $4.00 gallon, so a sign 15 cents cheaper still wins if you would use the same card there. It flips when the pricier station has a program or an Upside offer the cheap one lacks. $4.00 with Shell Gold and Upside comes to $3.69 after a 3% card, and beats a $3.85 sign with the same card at $3.73.
Every default and its source: Methods.