Is a detour for cheaper gas worth it? Fuel savings calculator
A lower unit price is only part of the decision. Compare savings on the fuel you buy with fuel used for the extra round trip. No account or location is required; your inputs stay in this page.
Method published on 10 October 2026 · Groupe Sentinelle
Calculate
Use the same currency throughout. Fictional examples, not current prices. Time, wear and consumption changes are excluded. A negative difference means extra cost.
Enter valid numbers. Fuel consumption must be greater than zero.
- Gross saving
- Extra travel and other costs
- Estimated net difference
Reference and method
In litres: net difference = quantity × (usual price − compared price) − extra distance × consumption ÷ 100 × fuel price − extra costs. In US gallons: detour fuel = extra miles ÷ US MPG.
Enter only the distance added to the trip you would make anyway, in both directions. Five miles to a station may add ten miles, while a station already on your route may add none. Real consumption changes with traffic, weather and stops. Add your own time or vehicle-wear estimate to other costs for a broader comparison.
Illustrative calculation: 50 litres at a difference of 0.04 per litre give a gross difference of 2.00 in the same currency. Subtract the fuel used for the detour before judging the benefit. This is not a current price or an average customer saving.
Read a price with its date.
Sources and publication schedules vary by region. The app shows a date or age when the source supplies one. Always confirm the price at the station. This website explains the app; it does not show live prices for your location.
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