Petrol Mileage Calculator
How do you calculate petrol mileage? Calculate petrol efficiency in MPG, km/L, or L/100 km.
Interactive inputs
Live result
30.00
MPG
Change an input to update the diagram.
Answer first
How do you calculate petrol mileage?
The Petrol Mileage Calculator measures fuel efficiency for gasoline-powered vehicles and displays results in MPG, km/L, or L/100 km. Whether you call it petrol or gasoline, this tool works for any gas vehicle to monitor and improve your real-world fuel economy.
Current calculator output
30.00
MPG
How it works
Petrol Mileage Calculator: inputs, formula, and result
By dividing the odometer miles by the gallons of standard gasoline pumped, this tool calculates the baseline miles per gallon for traditional internal combustion petrol engines.
Formula
Petrol MPG = Distance ÷ Fuel Used
Worked example
Driving 360 miles on 12 gallons of petrol gives 360 ÷ 12 = 30 MPG.
Pro tip: Track your petrol mileage over multiple fill-ups using the full-tank method: fill up completely, drive normally, fill up again, and divide the distance by the gallons added.
Personalized guidance
What changes the result for Petrol Mileage?
Petrol efficiency shifts based on the ethanol content of the fuel, spark plug health, air filter cleanliness, and the driver's tendency to speed on the highway. Traffic, tire pressure, vehicle load, terrain, driving style, weather, fuel price, and the quality of the input data can change the final result.
Estimated result condition
100%
Select factors that match this vehicle calculation.
When should you use this calculator?
Use this for standard daily tracking of your car's health. A sudden drop in calculated petrol mileage often signals an engine issue requiring maintenance.
Selected usePlan with Petrol Mileage Calculator
FAQ
FAQs about Petrol Mileage
3 questions
Question 1 of 3 is open
What is a good petrol mileage for a car?
A modern sedan should achieve 25-35 MPG combined. Subcompacts and hybrids can reach 35-55 MPG, while sports cars may only get 15-25 MPG.
How does octane rating affect petrol mileage?
Using higher octane fuel than your engine requires does not improve mileage. Only engines designed for premium fuel will see an efficiency gain of typically 1-3%.
Why does my real petrol mileage differ from the EPA estimate?
EPA tests are conducted in controlled lab conditions. Real-world factors like cold weather, short trips, AC use, and city traffic typically reduce mileage by 10-25%.
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