Gas Mileage Calculator

Distance

Enter the trip distance.

Distance Unit

Fuel Used

Amount of fuel consumed for this distance.

Fuel Unit

Optional: Fuel Price

Price per fuel unit

Per the selected fuel unit (e.g., $/gal or $/L).

Currency symbol

Displayed in cost results (default “$”).

Gas Mileage – Quick Cheat Sheet

MPG (US) = miles ÷ gallons (US).
km/L = kilometers ÷ liters.
L/100 km = (liters ÷ kilometers) × 100.
Conversions: 1 mile = 1.609344 km; 1 US gal = 3.785411784 L.
Cost: Trip cost = price per unit × fuel used (in the chosen fuel unit). Cost per mile/km = trip cost ÷ distance.
Units: Uses US gallon (not Imperial). Imperial gallon results will differ (~20% bigger).
Tips: For best accuracy, fill up fully, reset trip, drive normally, fill up again, and record distance and fuel added.

Edge cases & notes

Inputs must be positive. Extremely small fuel values can produce unrealistically high MPG.
All results are deterministic: no data is uploaded; everything runs in the browser/PHP page.
If you track fuel over multiple fill-ups, compute each tank then average weighted by distance for overall accuracy.