Worth The Drive?
Enter four numbers. Find out if the cheaper station actually saves you money — after the fuel you burn getting there.
Enter your numbers to see the verdict
Savings = gallons × (price difference) − detour fuel cost
How the Math Works
Transparency builds trust. Here is the exact formula — no black box.
Price difference savings
How much you save on the fill-up alone.
(your price − cheaper price) × gallonsDetour fuel cost
Fuel you burn driving there and back, valued at the replacement cost.
(round-trip miles ÷ your MPG) × cheaper priceNet result
If positive, it is worth the drive.
savings − detour costBreak-even distance
max round-trip = gallons × (price difference) × MPG ÷ cheaper priceNo external data. No estimates. Just arithmetic from the numbers you enter.
See It in Action
Click a scenario to load it into the calculator above and tweak the numbers.
Quick Questions
Why value detour fuel at the cheaper station's price?
Because that's what you'd pay to replace the fuel you burned — it's the true replacement cost.
What about wear and tear or my time?
This calculator covers fuel only. If your time is worth more than the savings, that's your call — but now you know the fuel math.
Does this work for diesel or EVs?
Same formula — enter price per gallon or per kWh, and your miles per gallon or miles per kWh.
What if I'm already planning to drive past the cheaper station?
Set round-trip distance to the extra miles beyond your existing route — if it's zero, the answer is always go.