EV vs Petrol Total Cost (5yr)

What this tool does

This calculator compares total cost of ownership for an electric vehicle and a petrol car over a user-defined period. It combines purchase price, cumulative fuel expense (electricity cost per mile for the EV; petrol cost per mile for the ICE), and straight-line compound depreciation at a constant annual rate. The result shows which powertrain costs less over the term and by how much.

How EV vs Petrol Total Cost (5yr) works

This tool calculates and compares the total cost of owning an electric vehicle and a petrol car over a chosen ownership period. It sums three components for each vehicle: the initial purchase price minus resale value (depreciation), the cumulative cost of energy over all miles driven, and outputs the difference. A positive result indicates the EV costs less; a negative result means the petrol car is cheaper over the term.

The formula

For each vehicle, Total Cost = Depreciation + Fuel Cost.
Depreciation = Purchase Price − Purchase Price × (1 − r)ⁿ, where r is the annual depreciation rate (as a decimal) and n is the number of years.
EV Fuel Cost = (Miles per Year × Years) ÷ EV Efficiency (mi/kWh) × Electricity Price (per kWh).
Petrol Fuel Cost = (Miles per Year × Years) ÷ MPG × 4.54609 (liters per imperial gallon) × Petrol Price (per liter).
The calculator subtracts Petrol Total from EV Total to find the net saving or penalty.

Where this method is most accurate

The compound depreciation model assumes a constant annual percentage decline, which approximates real-world resale curves for mainstream cars held 3–7 years. Fuel costs assume the entered efficiency figures (mi/kWh and MPG) remain constant and that electricity is purchased at the single rate entered (home charging or a blended average). The tool does not account for variation in depreciation rates between EV and ICE powertrains, insurance premiums, maintenance schedules, registration fees, or one-time incentives such as government purchase grants.

What this tool does not do

It does not incorporate servicing costs, tire replacement, insurance, registration fees, congestion or emissions-zone charges, battery replacement, or any government purchase grants or tax incentives. It does not predict future fuel prices, nor does it adjust depreciation curves for make, model, or market segment. The result is a comparative snapshot based on the inputs entered, not a forecast or recommendation to purchase either vehicle type.

Disclaimer

This calculator is an educational tool that performs arithmetic on user-supplied values. It does not constitute financial, tax, or vehicle-purchasing advice. Actual ownership costs depend on factors outside the scope of this model, including insurance rates, maintenance intervals, loan interest, and local incentives. Always verify efficiency and depreciation figures independently before making purchasing decisions.

Questions

Why does the calculator use the same depreciation rate for both vehicles?

The tool applies a single user-entered annual depreciation percentage to both the EV and petrol car to isolate differences in purchase price and fuel cost. In practice, EVs and ICE vehicles may depreciate at different rates depending on battery technology, manufacturer, and market demand; users can model that by running two separate scenarios with different rates.

Does this include insurance, registration fees, or maintenance?

No. The calculation covers only purchase price, depreciation, and energy costs. Insurance premiums, registration or road-use fees, servicing intervals, tire wear, and consumables vary by jurisdiction, insurer, and driving style, so they are excluded from this pure-math comparison.

How should I enter electricity price if I charge at home and at public stations?

Calculate a weighted average based on the proportion of miles charged at each rate. For example, if 80 percent of charging happens at home (0.28 per kWh) and 20 percent at rapid chargers (0.70 per kWh), the blended rate is 0.8 × 0.28 + 0.2 × 0.70 = 0.364 per kWh.

What if my EV efficiency varies with temperature or speed?

The tool uses a single constant efficiency figure. Real-world mi/kWh drops in cold weather and at highway speeds. To model a range, run the calculator twice—once with summer efficiency and once with winter—then average or use the lower figure as a conservative estimate.

Can I use this to compare hybrid or plug-in hybrid vehicles?

Only if you can express their energy consumption in consistent units. A plug-in hybrid drawing both electricity and petrol will require a blended cost-per-mile figure that accounts for the proportion of miles on each fuel, which this calculator does not compute automatically.

Sources & Methodology

The calculator applies compound annual depreciation: Resale Value = Purchase Price × (1 − r)^n. Fuel costs are computed from total miles driven, vehicle efficiency (mi/kWh or MPG using the imperial gallon = 4.54609 liters), and unit energy prices. Both totals are summed and subtracted to yield the net difference. The depreciation formula is standard in automotive finance; fuel-cost calculations follow unit-conversion arithmetic published in vehicle efficiency literature.