MPG Calculator
Calculate your car’s fuel efficiency in MPG (miles per gallon) or L/100km. Estimate fuel costs per mile and compare vehicle efficiency instantly with our UK-friendly tool.
Fuel Economy Calculator
Calculate MPG, L/100km, and fuel costs
Enter the total distance of your trip or tank
Enter the amount of fuel consumed
Enter the price you paid per unit of fuel
Your Fuel Economy
Efficiency and cost breakdown
Enter your distance and fuel used, then click Calculate to see your MPG and fuel costs.
Average Fuel Economy by Vehicle
Typical real-world MPG figures for common vehicle types in the UK.
| Vehicle Type | Average MPG (UK) | Average L/100km |
|---|---|---|
| Small City Car | 50 – 65 | 4.3 – 5.6 |
| Supermini | 45 – 55 | 5.1 – 6.3 |
| Family Hatchback | 35 – 45 | 6.3 – 8.1 |
| Executive Saloon | 30 – 40 | 7.1 – 9.4 |
| SUV (Small) | 35 – 45 | 6.3 – 8.1 |
| SUV (Large) | 25 – 35 | 8.1 – 11.3 |
| Sports Car | 20 – 30 | 9.4 – 14.1 |
Fuel Economy FAQ
Everything you need to know about calculating MPG and improving fuel efficiency.
MPG (Miles Per Gallon) is calculated by dividing the distance travelled in miles by the amount of fuel used in gallons. The formula is: MPG = Miles ÷ Gallons. For example, if you travel 300 miles and use 10 gallons of fuel, your MPG is 300 ÷ 10 = 30 MPG.
The difference lies in the size of the gallon. A UK (Imperial) gallon is 4.546 litres, while a US gallon is only 3.785 litres. Because the UK gallon is larger, a car will appear to have a higher MPG figure in the UK than in the US for the same fuel efficiency. To convert UK MPG to US MPG, multiply by 0.83. This calculator uses UK Imperial gallons by default.
To convert MPG (UK) to Litres per 100km (L/100km), use the formula: L/100km = 282.48 ÷ MPG. For example, 40 MPG is approximately 7.06 L/100km. Note that while higher MPG is better, lower L/100km is better.
A ‘good’ MPG depends on the vehicle type. Generally, a small city car should achieve 50-60 MPG. A family hatchback typically achieves 35-45 MPG. Large SUVs and performance cars may achieve 20-30 MPG. If your car is significantly lower than these ranges, it may indicate a mechanical issue or aggressive driving habits.
To improve MPG: 1) Keep tyres inflated to the correct pressure. 2) Remove unnecessary weight from the boot. 3) Drive at a steady speed and use cruise control on motorways. 4) Anticipate traffic to avoid heavy braking. 5) Use air conditioning sparingly, as it increases fuel consumption. 6) Remove roof boxes or racks when not in use to reduce drag.