What's included — and what isn't
The calculator counts the costs that differ most between the two cars and that you can pin down yourself: the purchase price after discounts and incentives, energy (fuel or electricity) and maintenance. It deliberately leaves out insurance, financing, registration and resale value, because those depend on the exact models, your location and your credit — but you can fold any of them in by adjusting the purchase price or the yearly maintenance figure for each car.
The formulas
Inside the calculator everything runs in metric units — litres, kilometres and kWh — and converts from what you enter: US miles per gallon (1 US gallon = 3.785 L), UK miles per gallon (1 imperial gallon = 4.546 L, so the same car shows a higher mpg in the UK) or L/100 km in Canada and Australia. That's why switching the country changes the units, not the answer.
Break-even is interpolated within the year, so “4.8 years” means part-way through year five. If the EV costs less to buy, it is cheaper from day one; if its running costs are higher (possible with expensive public charging and cheap fuel), it may never catch up.
Worked example
You drive 15,000 km a year. The fuel car uses 8 L/100 km at $1.50 per litre: 15,000 × 0.08 × 1.50 = $1,800 a year. The EV uses 18 kWh/100 km at 20¢ per kWh: 15,000 × 0.18 × 0.20 = $540 a year. With no maintenance difference, the EV saves $1,260 a year. If it costs $6,000 more to buy, it breaks even after 6,000 ÷ 1,260 = 4.8 years and is $6,600 ahead after ten.
Getting realistic inputs
- Efficiency: use official figures for both cars (FuelEconomy.gov in the US, WLTP figures in the UK and Australia, NRCan's Fuel Consumption Guide in Canada) or, better, your own real-world numbers. EV ratings are measured at the wall and already include charging losses.
- Electricity price: if you'll charge mostly at home on an off-peak tariff, use that rate; if you'll rely on public chargers, blend the prices — our EV Charging Cost calculator does the blending for you.
- Price changes: the defaults keep fuel and electricity prices flat. Try a few percent per year on either to see how sensitive the answer is — we don't forecast prices.
Reference prices used as defaults
| Default | Country | Value | Source and period |
|---|---|---|---|
| Gasoline / petrol | US | $4.331/gal | U.S. EIA, Gasoline and Diesel Fuel Update, week of 12 Oct 2026 |
| Gasoline / petrol | UK | 175.28p/L | GOV.UK (DESNZ), Weekly road fuel prices, week of 12 Oct 2026 |
| Gasoline / petrol | Canada | 173.80¢/L | Statistics Canada, Table 18-10-0001-01, August 2026 (monthly) |
| Gasoline / petrol | Australia | — | No verified national figure on file — the field asks for your own rate. |
| Electricity | US | 18.31¢/kWh | U.S. EIA, Electric Power Monthly, Table 5.6.A, July 2026 (preliminary) |
| Electricity | UK | 26.32p/kWh | Ofgem, 1 Oct – 31 Dec 2026 |
| Electricity | Canada | — | No verified national figure on file — the field asks for your own rate. |
| Electricity | Australia | — | No verified national figure on file — the field asks for your own rate. |
Where a cell is empty, enter your local price — we only pre-fill official, dated national figures.
Sources
- U.S. EIA — Gasoline and Diesel Fuel Update (weekly retail prices)
- GOV.UK — Weekly road fuel prices
- Statistics Canada — Table 18-10-0001-01, Monthly average retail prices for gasoline and fuel oil
- FuelEconomy.gov — Compare side-by-side (official US mpg and kWh/100 mi)
- U.S. EPA — EV ratings include charging losses
Results are estimates based on the figures you enter and the stated assumptions. They are not financial, tax, legal or engineering advice. Spotted a problem? Tell us.