EV vs Gas Cost Calculator: What Ownership Actually Costs Over Time – Explained
Battery size versus engine displacement, fuel versus electricity, and all the running costs in between — our calculator estimates how an EV and a petrol or diesel car compare over years of ownership.
Every EV-versus-petrol comparison online seems to pick two specific cars, run the numbers, and call it a day. The problem is that the moment you drive a different model, in a different country, at a different fuel price, the whole comparison falls apart. Our calculator takes a different approach: instead of comparing named vehicles, it compares vehicle classes, using battery size for EVs and engine displacement for petrol or diesel cars. That covers effectively every mainstream car on the road without pretending to know which exact model you’re cross-shopping.
Set your fuel prices and driving pattern, pick a battery size and an engine, and it totals up energy or fuel, maintenance, insurance, and registration over however many years you plan to keep the car.
Try the EV vs Gas Cost Calculator
Enter your fuel prices and mileage, then pick a battery size or engine to get an instant cost comparison.
Open the Calculator →This is an estimation tool, not a quote. It uses typical consumption and running-cost figures for each battery or engine size band, not manufacturer-specific data, because those vary by model, driving style, and climate. Treat the output as a starting point for your own comparison, not a final number.
How to use it
- Set your fuel prices and driving pattern. Enter your local petrol and diesel prices, how many km you drive a year, and how long you plan to keep the car (1 to 10 years).
- Pick your EV battery size. Choose from four tiers — 40, 60, 80, or 100+ kWh — each with example models so you can match it to the car you’re actually considering.
- Pick a gas engine size. Choose a displacement from 1000cc up to 3000cc, split into petrol and diesel groups, each with its own consumption figure.
- Read the comparison. You’ll get a total cost for each vehicle over your chosen ownership period, a per-year and per-km breakdown, and the total savings one option offers over the other.
What’s actually being calculated
The running totals are built from four components for each vehicle: energy or fuel cost, maintenance, insurance, and registration. Here’s exactly what feeds into each one.
Energy and fuel cost
EV energy use is estimated by battery tier, using a fixed electricity price behind the scenes. Petrol and diesel consumption is estimated by engine size and fuel type, multiplied by whichever fuel price you entered.
| EV battery tier | Estimated range | Example models |
|---|---|---|
| 40 kWh (small) | 200–250 km | Nissan Leaf, Hyundai Ioniq |
| 60 kWh (mid-size) | 250–350 km | Tesla Model 3, VW ID.4 |
| 80 kWh (large) | 300–450 km | Tesla Model Y, Kia EV9 |
| 100+ kWh (premium) | 400–500+ km | Mercedes EQS, BMW iX |
| Engine size | Petrol consumption | Diesel consumption |
|---|---|---|
| 1000 cc | 6.2 L/100km | — |
| 1200 cc | 6.8 L/100km | 4.8 L/100km |
| 1500 cc | 7.2 L/100km | 5.2 L/100km |
| 1800 cc | 8.0 L/100km | — |
| 2000 cc | 8.5 L/100km | 5.8 L/100km |
| 2500 cc | 9.5 L/100km | 6.5 L/100km |
| 3000 cc | 10.5 L/100km | — |
Maintenance
Maintenance scales with distance rather than time, on the logic that a car driven twice as far needs roughly twice the servicing. EVs are costed at a lower rate per km than combustion cars, reflecting the absence of oil changes, timing belts, and exhaust work.
Insurance and registration
These are set at a flat annual rate for both vehicle types in this version of the calculator, since actual premiums and registration or road tax bands vary too much by country, driver profile, and insurer to estimate reliably from battery size or engine cc alone. If you have a real quote for either vehicle, mentally add the difference to the total the calculator gives you — it will move the comparison more than most people expect.
What the calculator does not include: purchase price, depreciation, home charger installation, battery degradation over time, or financing costs. Those factors often matter more to total cost of ownership than running costs, but they depend on a specific car, deal, and market — which is exactly what a class-level tool like this can’t assume.
Worked example
Here’s what the calculator produces at its default settings — petrol at €1.68/litre, diesel at €1.72/litre, 12,000 km a year, over a 5-year ownership period — comparing a 40 kWh EV against a 1000cc petrol car:
5 years, 12,000 km/year, 1000cc petrol vs 40 kWh EV
| 40 kWh EV | 1000cc Petrol | |
|---|---|---|
| 5-year total | ≈ €4,300 | ≈ €11,350 |
| Per year | ≈ €860 | ≈ €2,270 |
At these defaults, the EV comes out roughly €7,000 cheaper to run over five years — a little over 60% less. That gap narrows in markets with higher electricity prices or cheaper petrol, and widens with higher annual mileage, since more distance driven means more of the running cost is fuel or energy rather than the flat insurance and registration components.
Because none of the cost components in this calculator include a one-off purchase price, the per-year figure stays constant no matter how many years of ownership you select — a 1-year comparison and a 10-year comparison will show the same annual cost, just multiplied differently. What changes with your ownership period is the total, and how much time you have to recoup any price difference at the point of purchase, which this tool intentionally leaves out of the sum.
Which battery or engine size matches your car?
If you’re not sure which tier to pick, match on real-world range or engine badge rather than trying to guess exactly:
- 40 kWh: compact EVs with a real-world range around 200–250 km — think early Nissan Leaf or Hyundai Ioniq territory.
- 60 kWh: the current EV mainstream — most mid-size hatchbacks and saloons like the Tesla Model 3 or VW ID.4 sit here.
- 80 kWh: larger EVs and SUVs built for longer range, such as the Tesla Model Y or Kia EV9.
- 100+ kWh: premium, long-range EVs — Mercedes EQS and BMW iX class vehicles.
For a petrol or diesel car, the engine size is usually printed on the badge or in the vehicle registration document — round to the nearest bracket in the tables above.
Why battery size and engine cc instead of specific models
A calculator built around named vehicles only works for the handful of cars it was built for, and goes stale the moment a manufacturer updates a model year or a country changes its fuel price. Battery size and engine displacement are used here because they’re published for effectively every EV and combustion car on sale, they correlate reasonably well with real-world running costs, and they let one tool cover a compact hatchback and a mid-size SUV without maintaining a spreadsheet of every trim level in Europe.
The trade-off is precision. Two cars with the same displacement can have meaningfully different consumption depending on aerodynamics, weight, and gearing, and the same is true of two EVs with the same battery size. Treat the output as a class-level comparison, then narrow it down with a specific model’s official consumption figures once you know roughly which segment you’re looking at.
Mr Wangdoo’s take: people tend to fixate on the fuel-versus-electricity line because it’s the most visible number, but in this calculator the flat insurance and registration costs and the per-km maintenance rate carry a lot of the total too. If you’re comparing a specific EV and a specific petrol car in real life, get an actual insurance quote for both before you trust any tool’s default — including this one.
Why doesn’t the calculator ask for a specific car model?
Because matching every model on sale to accurate, current consumption data isn’t something a single tool can maintain reliably. Battery size and engine displacement give a reasonable class-level estimate that stays useful regardless of which specific model you’re weighing up.
How accurate are the consumption figures used?
They’re fixed averages assigned to each battery tier or engine bracket, not figures for any one car. Real-world consumption on both EVs and combustion cars can swing well outside these figures depending on driving style, terrain, and climate, particularly for EV range in cold weather.
Can I change the insurance, maintenance, or registration assumptions?
Not in this version — those are calculated internally rather than entered by you. What you can control is the fuel prices, annual mileage, and ownership period, which are the inputs that vary most from person to person.
Does the calculator account for battery degradation, resale value, or purchase price?
No. All three are highly dependent on the specific model, battery chemistry, climate, financing terms, and local market, which puts them outside what a class-level calculator can reasonably estimate. They’re worth researching separately for any specific EV or petrol car under consideration.
Run Your Own Numbers
Get an instant cost breakdown for your battery size or engine cc, at your own fuel prices and mileage.
Open the Calculator →Sources
- Consumption and range figures are typical values assigned per battery tier and engine displacement bracket within the calculator, not manufacturer test data for a specific vehicle.
- Fuel price fields are user-editable and reflect the rates entered at time of use.
