About Fuel Economy Calculator

Calculate MPG, fuel costs, and efficiency metrics for vehicles. Part of the DevTools Surf developer suite. Browse more tools in the Calculators collection.

Use Cases

• Calculate the annual fuel cost difference between two car models before purchasing.
• Estimate road trip fuel cost based on distance and vehicle efficiency.
• Track MPG degradation over time to detect engine or tire pressure issues.
• Compare internal combustion vs. hybrid cost-per-mile for a specific commute pattern.

Tips

• Enter fuel price in local currency per liter or gallon — the tool converts internally so both MPG and L/100km users get accurate cost figures.
• Compare two vehicles simultaneously to calculate annual savings from switching to a more efficient model.
• Use the CO2 emissions output to estimate your vehicle's annual carbon footprint for sustainability reporting.

Fun Facts

• The US EPA fuel economy label became mandatory on all new cars in 1977, following the 1973 oil crisis — before that, manufacturers self-reported MPG with no standardized test.
• An idling car gets 0 MPG while consuming 0.16-0.32 gallons of fuel per hour, making stop-and-go traffic measurably worse than highway driving even at higher highway speeds.
• The EU uses L/100km while the US uses MPG — they measure the same thing inversely. A car rated 30 MPG equals roughly 7.8 L/100km. Converting requires dividing 235.2 by the value.

FAQ

Does it support electric vehicles?

Yes — switch to kWh/100km or miles/kWh mode and enter your electricity price per unit to get cost-per-mile equivalent figures alongside ICE vehicles.

How accurate is the CO2 estimate?

It uses the EPA/EU standard emission factors: 8.887 kg CO2 per gallon of gasoline and 10.180 kg per gallon of diesel. Results match official lifecycle estimates within 2-3%.

Can I track multiple fill-ups over time?

Enter odometer readings and fuel amounts for each fill-up and the tool computes rolling average MPG, highlighting outlier readings.