Cost-Plus vs Fixed Discount Calculator
Compare discount models
Use the same gallons for both models to compare estimated total cost.
When to Use This Calculator
Use this calculator when you are comparing a cost-plus fuel price against a fixed cents-per-gallon discount. The tool is useful only when the cost-plus base price, markup and retail reference price are known or clearly quoted for the same location or lane.
Input Fields
| Field | What to enter | What to verify |
|---|---|---|
| Retail price per gallon | The posted or quoted retail price used for the fixed-discount comparison. | Whether it is cash, credit, retail pump or another reference price. |
| Cost-plus base price | The base price before markup. | How the provider defines the base price and how often it changes. |
| Markup per gallon | The cents or dollars added to the base price. | Whether taxes, network fees or transaction fees are included. |
| Fixed discount cents | The stated cents-per-gallon discount. | Eligible locations, products, gallon minimums and discount caps. |
| Gallons | The gallons you want to compare under both models. | Use gallons that can realistically be purchased under both programs. |
Formula
Cost-plus total = (cost-plus base price + markup) × gallons. Fixed-discount total = (retail price - fixed discount per gallon) × gallons.
How to Read the Result
The lower total is not automatically the better program. Network access, payment timing, fees, reporting and driver workflow can change the practical value. Run the comparison with several real fuel stops if the provider pricing varies by location.
Related reading: cost-plus fuel discounts, fixed-discount fuel cards and retail-minus fuel discounts.
Common Mistakes
The common mistake is comparing a cost-plus number from one location with a retail-minus or fixed-discount number from a different location. Use the same lane, stop type and gallon assumption whenever possible. If the base price is not defined, the cost-plus side of the comparison is incomplete.
Do not ignore fees after finding the lower fuel price. Monthly, transaction and out-of-network fees can change the result, especially for one-truck businesses or routes with frequent smaller fills.
Records to Keep With the Estimate
Save the base-price definition, markup, retail reference price, gallons, date and location used for the calculation. If the provider uses a rack-related or wholesale-related base price, ask how that base is updated and whether taxes or network costs are already included.
Related Terms
Cost-plus discount, fixed discount, retail-minus discount and base fuel price explain the pricing terms used here.