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Gas vs Electric Car Cost

Enter annual mileage, fuel price and consumption, then electricity price and consumption, to see cost per kilometre for both powertrains plus yearly and cumulative savings, computed locally in your browser.

Whether an electric car really costs less to run is asked by almost everyone buying one, and the answers online contradict each other: one person quotes off-peak home charging at a few cents a kilometre, another quotes public fast charging at well over a dollar, so the conclusions clash. Broken down it is a multiplication — cost per kilometre is the price multiplied by the consumption per 100 km, divided by 100.

Enter your own conditions — annual distance, the fuel consumption of the petrol car, the consumption of the electric one, and local prices for both — and the cost per kilometre sits side by side, with the annual difference and the five-year saving worked out. Comparing energy cost alone is deliberate: purchase price differences, insurance and servicing each have their own logic, and folding them together only muddies the account.

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How to use

  1. Enter annual mileage.
  2. Enter the fuel price and consumption for the petrol car.
  3. Enter the electricity price and consumption for the electric one.
  4. Read the cost per kilometre and the yearly and cumulative savings.

How it works

How per-km cost is computed

Per-km cost = unit price x (consumption per 100 km / 100): fuel at 7.5/L and 8 L/100km gives 0.6 per km; power at 0.5/kWh and 13 kWh/100km gives 0.065 per km. Annual cost = per-km cost x annual mileage, cumulative = annual cost x years; all three are linear, so changing any parameter shows directly how the result shifts.

What electricity price to enter

Enter the electricity price for your actual charging: with a home charger on off-peak rates, use the off-peak price (around 0.3 in many areas); relying solely on public fast charging, try 1.2-1.8; for a mix, estimate a weighted price. Fuel similarly — 92 and 95 differ by over half a unit, so enter the grade you usually use. If unsure, compute both extremes — the gap is itself part of the answer.

Why purchase and maintenance are excluded

Energy cost is only part of car ownership: EVs usually have no purchase tax and cheaper maintenance, but insurance is generally pricier and battery depreciation and residual value are another ledger; gasoline cars hold value more steadily but fuel prices fluctuate long-term. These factors have different dimensions and vary by car, so forcing them into one formula only distorts — this tool cleans up the energy account, and you estimate the rest by specific model.

How to use the result

Use the comparison back in the decision: the higher the annual mileage and the wider the fuel-electric price gap, the more obvious the EV's energy advantage — 20,000 km a year and 5,000 km a year are two entirely different questions. If your annual mileage is low and you lack home charging, the energy difference may be far smaller than the purchase-price difference, and whether you save shouldn't hinge only on fuel and electricity prices.

Code example

JavaScript Cost per kilometre: price × consumption per 100km / 100 

const fuelPerKm = 7.8 * (8.0 / 100);   // fuel at 7.8 per litre, 8 L/100km → 0.624
const elecPerKm = 0.6 * (15 / 100);    // power at 0.6 per kWh, 15 kWh/100km → 0.09

fuelPerKm / elecPerKm;                 // ≈ 6.9× cheaper

// Fuel and electric cars must both be expressed per kilometre before comparing
// Home charging and public chargers differ a lot — use your own charging habits

JavaScript Annual cost and an N-year total 

const kmPerYear = 15000;
const fuelYear = fuelPerKm * kmPerYear;   // 9360 per year
const elecYear = elecPerKm * kmPerYear;   // 1350 per year

// N-year total = annual cost × N (compare 1~15 years)
// Energy only: the purchase-price gap, insurance, servicing and resale need separate weighing

FAQ

What electricity consumption is reasonable?

Home EVs in city conditions are mostly 12-16 kWh/100km, rising clearly with winter heating and higher at highway cruise. Take a middle value for your climate and commute; if unsure, use the average from your car's computer — a real figure after some driving is more meaningful than a marketed one.

Why is my gasoline car's per-km different from this?

The most common difference is conditions: the dashboard figure is smoothed by the computer for recent conditions, so congested commuting is worse; also discounted stations price fuel well below list. Record two full tanks' mileage and enter the measured consumption — most accurate.

How do hybrids fit the comparison?

Plug-in hybrids at depleted-battery fuel consumption (4-5 L) can be entered as a gasoline car, with self-charged electricity not counted separately; range-extenders and plug-ins that commute mostly on electricity can combine "electric cost for EV miles + fuel cost for depleted miles" into one equivalent cost by proportion. The tool computes a single convention — split hybrid conditions yourself.

What comparison period is suitable?

Your expected ownership years: a 3-5 year replacement cycle means 5 years. Cumulative savings extrapolate linearly, so longer periods give larger numbers, but battery degradation and fuel-price swings aren't reflected — long-period results are for magnitude, not a promise.

How do I handle peak/off-peak pricing?

Where time-of-use pricing applies, enter the weighted average of the prices at times you can charge. For example 70% at off-peak 0.3 and 30% at flat 0.6 gives about 0.39. You can also compute off-peak and flat separately to see how much "sticking to off-peak charging" matters.

EVs cost more in insurance and less in maintenance — why not include them?

Insurance and maintenance differences vary by model, region and claim history with no universal coefficient, and hardcoding them into the formula misleads. Recommended use: settle the energy account here, then list the candidate model's actual insurance quote and maintenance schedule separately — adding both gives a complete comparison.

How do I estimate annual mileage accurately?

For commuters, estimate as "one-way km x 2 x weekly workdays x 50 weeks" plus holiday trips; if unsure, check the traffic-authority platform's annual mileage or your car's records. Mileage is this tool's most sensitive parameter — doubling it doubles annual cost, worth a minute to enter accurately.