Fuel Card Savings Calculator: Estimate Discounts and True Savings for Truckers

What each input means

The form takes one month of fueling for the whole fleet, in the order below. The discount and fee boxes come from a card's terms, and you can compare fuel cards for truckers on those same terms.

• Number of trucks. Trucks that carry a card. Each one pays the monthly card fee.
• Average MPG. Miles per gallon across the fleet, idling included.
• Monthly miles per truck. Every mile a truck runs in a month, loaded and empty.
• Fuel price. Dollars per gallon. The default is $5.967, EIA's U.S. No. 2 diesel retail average for the week of 7 September 2026.
• Discount type. Cents per gallon takes a fixed amount off each gallon. Percentage takes a share of the pump price.
• Discount. For cents per gallon, enter dollars: 0.05 is 5 cents. For a percentage, enter the percent: 2.5 is 2.5%.
• In-network gallons. The share of your gallons bought at stations that honor the discount.
• Transaction fee. Charged on every fill, in or out of network.
• Monthly card fee. Per card, per month.
• Out-of-network fee. An extra charge on each fill outside the network, on top of the transaction fee.
• Average gallons per fill. Used to count fills, which sets the per-fill fees.

Two of these boxes are easy to guess wrong, and a month of card statements settles both. The in-network share is the gallons that earned a discount divided by all the gallons bought. Gallons per fill is the statement's total gallons divided by its number of transactions. A driver who tops off often makes more fills from the same gallons and pays more transaction fees.

The discount assumptions behind the result

• The discount applies only to in-network gallons. At 80% in network, 80% of gallons earn it and the other 20% earn nothing.
• A cents-per-gallon discount is the same at any pump price. A percentage discount is the pump price times the percent, so 2.5% of $5.967 is 14.9 cents a gallon.
• Fills are monthly gallons divided by gallons per fill. Every fill pays the transaction fee, and out-of-network fills also pay the out-of-network fee.
• The card fee is charged once per truck per month.
• The default card terms (5 cents a gallon, 80% in network, $1.50 a fill, $10 a card, $3.00 out of network, 150 gallons a fill) are placeholders for your own contract, not market averages. The published terms we check for each card, and the dates we checked them, are set out in our rating methodology.
• Break-even gallons is the monthly volume at which savings cover the card fees, after the per-fill fees are taken out of each gallon's discount. If the per-fill fees are larger than the discount per gallon, no volume breaks even and the calculator shows "Never".
• A break-even above half your monthly gallons triggers a warning, because a month at half your usual miles would then lose money on the card.
• The result bands (2.5% or more of fuel spend, 1.5%, 0.5% and below) are this calculator's own bands, not industry figures.

A worked example in $/gallon, $/fill and $/month

One truck runs 10,000 miles a month at 6.5 mpg and buys diesel at EIA's $5.967, on the calculator's default card terms: 5 cents a gallon off, 80% of gallons in network, 150 gallons a fill, a $1.50 transaction fee, a $3.00 out-of-network fee and a $10 monthly card fee. It buys 1,538.5 gallons a month for $9,180 over 10.3 fills.

That is $30.00 a month and $360 a year, or 0.33% of the $9,180 fuel bill, which the calculator rates as low. Each gallon nets 2.6 cents after per-fill fees, so 385 gallons a month covers the $10 card fee, about a quarter of what the truck buys. Counting the discount on all 1,538.5 gallons instead of the in-network share would add $15.38 a month that the card never pays.

On a percentage card, only the discount line changes. For the same truck:

The price basis: EIA's weekly diesel series

The default fuel price is $5.967 a gallon, the U.S. No. 2 diesel retail price for the week of 7 September 2026 in the U.S. Energy Information Administration's Gasoline and Diesel Fuel Update, released on 9 September 2026. EIA updates the series every week. A percentage discount grows with the price, and a cents-per-gallon discount stays put:

The 36.8-cent rise between the last two weeks adds $566 to one truck's monthly fuel bill.

For scale, fuel averaged 48.2 cents a mile in the American Transportation Research Institute's 2025 operating cost data, released on 15 July 2026. At $5.967 and 6.5 mpg it is 91.8 cents. The national average is a starting point, so enter the price on your own receipts.

What this calculator does not account for

• One discount applies to every in-network gallon, even where the discount varies by station.
• Some cards price from the station's cost instead of the pump price. For those, enter the average discount your statements show.
• Rebates paid later, sign-up offers and volume tiers are left out.
• Setup, annual, card replacement, late payment and minimum-volume charges are not counted.
• Payment terms, credit limits and interest on a balance are outside the result.
• The card fee counts once per truck, so a fleet whose trucks share cards pays less in card fees than the result shows.
• IFTA purchase records, spending controls and maintenance discounts carry no dollar value here.
• Fuel is one line in a trucking budget. The Trucking Startup Cost Calculator covers the costs of getting a truck on the road.