Diesel vs Petrol vs EV Running Cost Comparison
Compare the yearly fuel and charging cost of a petrol, diesel and electric version of your drive. Enter your annual distance plus the economy and energy price for each drivetrain you want to weigh up, and see the cost per 100 km, the annual running cost and which option is cheapest to fuel.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter your annual distance in kilometres (how far you drive in a typical year).
- For each drivetrain you want to compare, enter BOTH its economy and its energy price — petrol/diesel as L/100km and $/L, an EV as kWh/100km and $/kWh. Leave a drivetrain blank to skip it.
- Read off the annual running cost and cost per 100 km for each option, and the 'cheapest to run' result at the bottom.
How it works
For a fuel vehicle the cost per 100 km is economy (L/100km) multiplied by the fuel price ($/L). For an EV it is consumption (kWh/100km) multiplied by the electricity price ($/kWh). The annual cost is that per-100km figure scaled by your yearly distance: annual = cost per 100 km × (annual km ÷ 100). A drivetrain is only included when both its economy and its price are entered, so you can compare any two or all three. The tool then flags the option with the lowest annual energy cost.
Worked example
Worked example. Driving 15,000 km/yr: a petrol car at 8 L/100km and $2.00/L costs 8 × 2.00 = $16.00/100km, or $2,400.00/yr. A diesel at 7 L/100km and $2.10/L costs $14.70/100km, or $2,205.00/yr. An EV using 18 kWh/100km at $0.30/kWh costs $5.40/100km, or $810.00/yr — the cheapest to run here.
Common mistakes
- Entering an economy without its matching price (or vice versa) — a drivetrain is only calculated when both boxes are filled.
- Comparing energy cost alone: this excludes servicing, tyres, registration, insurance and depreciation, which differ by drivetrain and can outweigh the fuel gap.
- Mixing up units — petrol and diesel use litres per 100 km and dollars per litre, while the EV uses kilowatt-hours per 100 km and dollars per kilowatt-hour.
Frequently asked questions
Does this include the cost of buying the car or the battery?
No. It compares running (energy) cost only. Purchase price, depreciation, servicing, tyres, rego and insurance are separate and should be added for a full whole-of-life comparison.
Can I compare just two drivetrains?
Yes. Fill in the economy and price for only the options you care about — for example petrol vs EV — and leave the third blank.
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Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.