Fuel & Running Cost Calculators

Diesel vs Petrol: How Running Costs Are Actually Calculated

Comparing diesel and petrol running costs isn't just about which fuel is cheaper per liter — it's the combination of price per liter and the vehicle's mileage in that fuel that determines the actual monthly cost, which is why a costlier-per-liter fuel can still work out cheaper to run overall.

How Fuel Economy Is Calculated — km/L, MPG, and L/100km

Fuel economy can be expressed three different ways — kilometers per liter, miles per gallon, or liters per 100 kilometers — and two of these three measures run in the opposite direction from the third, which is why comparing fuel economy figures from different sources can be confusing unless you know which measure you're looking at.

How Your Vehicle's Fuel Efficiency Is Calculated

Fuel efficiency is distance traveled divided by fuel used — expressed as km/l, liters per 100km, or miles per gallon — measured most accurately by filling the tank completely at both ends of a trip.

Why Your Actual Mileage Changes Your Road Trip Budget

Feeding a real, measured mileage figure into a road trip budget instead of an assumed one can change the estimated total cost by a meaningful amount — and parking is a further real expense that neither calculator includes automatically.