EV vs petrol calculator — emissions and cost savings | Decarb
Mini-calculator · Transport
EV vs petrol: how much would you save?
Enter your current car and annual mileage. The calculator estimates estimated CO₂e reduction and fuel cost savings from switching to an electric vehicle, using your state's grid emission factor from eGRID 2023 (EPA).
01 Your current car
US average is 28 MPG. Check your window sticker or fueleconomy.gov.
MPG
Typical: 1.0–1.2L (small hatchback), 1.5–2.0L (family car), 2.5–3.5L (SUV / pickup). Converted to MPG using EPA vehicle class data.
litres
Used to estimate MPG from engine size.
02 Annual mileage
US average is 13,500 miles/year (FHWA 2023). Your odometer difference over 12 months is the most accurate figure.
miles/yr
03 Your US state
Sets the grid emission factor for your electricity. This significantly affects the EV estimate — Vermont is nearly zero-carbon; West Virginia is coal-heavy.
04 Payback estimate (optional)
If you enter the additional upfront cost of an EV over your current car (or a comparable model), the calculator will estimate how many years it takes for fuel savings to break even. Leave blank to skip.
Example: if the EV costs $45,000 and the petrol equivalent costs $30,000, enter $15,000. Federal $7,500 tax credit (if eligible) can reduce this figure.
USD
05 Manufacturing emissions (optional · advanced)
Producing an EV generates more CO₂e than producing a petrol car — primarily from battery manufacturing. This section estimates that one-time "manufacturing debt" and how long it takes your operational savings to pay it back. These are range estimates with significant uncertainty — figures vary by battery size, chemistry, factory energy source, and country of manufacture.
Larger batteries mean more manufacturing emissions. Select the closest match to the EV you are considering.
Methodology caveat
Manufacturing emission estimates vary widely across studies — typically ±30–50% depending on factory energy source, battery chemistry, supply chain assumptions, and functional unit. The ranges shown here draw on ICCT (2024, 2025), IVL Swedish Environmental Research Institute (2022), and Argonne GREET (2025). They should be treated as indicative, not precise. A battery manufactured using renewable energy may have 50–70% lower manufacturing emissions than one made on a coal-heavy grid. The calculator uses the mid-point of published ranges and displays the full range.
Manufacturing emissions are one-time — to compare them with annual operational savings, they are spread across the vehicle's useful life. Default: 12 years (US average vehicle age at retirement, BTS 2024).
years
Please check your inputs — all required fields must be filled in with valid numbers.
Estimated annual savings from switching to an EV
Switching to an EV could save an estimated — tons CO₂e and — per year.
—
tons CO₂e per year
Estimated emissions saved
—
per year
Estimated fuel cost saved
—
years to break even on fuel savings alone
Estimated payback period
Manufacturing emissions (one-time estimate)
Petrol car
—
tons CO₂e
EV (mid estimate)
—
tons CO₂e
EV manufacturing premium
—
tons CO₂e (range)
Sources: ICCT (Negri & Bieker, July 2025); ICCT US lifecycle analysis (July 2024); IVL Swedish Environmental Research Institute (2022); Argonne GREET 2025. Range estimates only — actual manufacturing emissions vary significantly by factory energy source, battery chemistry, and supply chain. Mid-point of published ranges used as default.
Cumulative lifetime emissions
Including manufacturing + operational emissions over vehicle lifetime
Petrol car
Electric vehicle
EV manufacturing range
How the estimate is calculated
Item
Petrol car
EV equivalent
Emission estimates use eGRID 2023 state-level grid factors (EPA), 8.887 kg CO₂/gallon for petrol, and 10.180 kg CO₂/gallon for diesel. EV efficiency is modelled at 3.5 miles/kWh (EPA 2024 US fleet average). Fuel prices use EIA 2024 averages: petrol $3.30/gal, diesel $3.90/gal, electricity $0.16/kWh. Figures are estimates — actual savings depend on driving conditions, EV model, and local fuel prices. Results expressed in tons CO₂e per year.
