Gas Savings CalculatorPetrol Savings Calculator
Compare fuel spending on your current car with charging a Tesla. Mix home charging and Supercharging, factor in rising gas prices, and see when the savings cover the price gap.
Compare what you spend at the pump in your current petrol or diesel car with charging a Tesla. Mix home charging (standard rate or an off-peak EV tariff) with Supercharging, allow for rising fuel prices, and see when the savings cover the price gap.
You save per year
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10-year savings
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with gas price changewith fuel price change
Break-even
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CO₂ avoided
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tailpipe, per year
Cumulative cost over 10 years
Fuel + maintenance (+ price gap for the Tesla)Cost per mile
Annual running cost
Year by year
How this is calculated
- Gas cost = miles ÷ mpg × gas price, rising each year by the price change you set.
- Tesla energy = miles × Wh/mi ÷ 1000. Home kWh are increased by the charging-loss percentage; Supercharger kWh are billed as delivered.
- Break-even is the month where cumulative savings exceed the purchase price gap.
- CO₂ uses 8.89 kg per gallon of gasoline burned (EPA). Upstream grid emissions are not subtracted.
- Fuel cost = miles ÷ mpg (imperial) × 4.546 litres per gallon × pump price per litre, rising each year by the price change you set.
- Tesla energy = miles × Wh/mi ÷ 1000. Home kWh are increased by the charging-loss percentage; Supercharger kWh are billed as delivered.
- Break-even is the month where cumulative savings exceed the purchase price gap.
- CO₂ uses about 2.31 kg per litre of petrol (≈10.5 kg per imperial gallon) or 2.68 kg per litre of diesel, tailpipe only. Emissions from generating the electricity are not subtracted.
Why does my Tesla use more energy than the EPA number?
Cold weather, high speeds, short trips, cabin heating and sentry mode all raise consumption. Owners commonly see 10–30% above the rated figure in winter. Adjust the Wh/mi field to match your trip meter.
Where do the default prices come from?
State averages for residential electricity and regular gasoline, rounded. They change often, so enter your own utility rate and local pump price for the best estimate. See Methodology.
Why does my Tesla use more energy than the official figure?
Cold weather, motorway speeds, short trips, cabin heating and Sentry Mode all raise consumption, and WLTP figures are optimistic to begin with. Owners commonly see 10–30% above the rated figure in a British winter. Adjust the Wh/mi field to match your trip meter.
Should I use my standard rate or an EV tariff?
If you're on an off-peak EV tariff and charge overnight, use that rate (typically 7–9p/kWh for around six hours a night) — it's the single biggest lever on your savings. If you charge whenever you plug in on a standard capped tariff, use your unit rate (around 26–28p). If you do a bit of both, use a blend.
Where do the default prices come from?
Rounded regional averages for the capped electricity unit rate and unleaded petrol; diesel is assumed about 5p/L dearer. Prices change often, so enter your own tariff and local pump price for the best estimate. See Methodology.