EV vs Gas Savings Calculator

How it works

EV cost = annual miles ÷ EV efficiency × electricity rate. Petrol cost = annual miles ÷ mpg × petrol price. Yearly savings = petrol cost − EV cost. The 5-year figure simply multiplies the yearly saving by five. It compares fuel only — not purchase price, insurance or maintenance.

Worked example, step by step

Take the defaults: 12,000 miles a year, an EV doing 3.5 mi/kWh at $0.17/kWh, versus a 30 mpg petrol car at $3.50/gallon.

EV fuel cost = 12,000 ÷ 3.5 × $0.17 = $582.86 a year.

Petrol fuel cost = 12,000 ÷ 30 × $3.50 = $1,400 a year.

Yearly saving = $1,400 − $582.86 = $817.14, or about $4,086 over five years — on fuel alone.

The gap widens if you drive more miles, if petrol is expensive relative to electricity, or if you charge on cheap off-peak power. It narrows — and can even flip to petrol being cheaper — where electricity is very expensive and fuel is cheap, which is exactly why entering your own local prices matters.

What this comparison leaves out (and why it still matters)

This tool deliberately compares fuel cost only, because that is the number people can act on immediately and verify against their own bills. But a full ownership comparison has three other pieces worth knowing.

Upfront price: EVs still often cost more to buy than a comparable petrol car, though incentives, tax credits, and falling prices have narrowed the gap. The fuel saving above is what pays that difference back over time — divide the price gap by the annual fuel saving to get a rough payback in years.

Maintenance: EVs have far fewer moving parts — no oil changes, no exhaust, less brake wear thanks to regenerative braking — so they typically cost less to maintain, which adds to the running-cost advantage this calculator already shows.

Public charging: the numbers here assume home charging. If you rely on public DC fast charging, your per-kWh cost can be 2–4× higher, which can erase much of the fuel saving. EVs are cheapest for people who can charge at home overnight.

Resale and battery life: modern EV batteries are lasting well and are typically warrantied 8 years or 100,000 miles, but resale value and battery health are real factors in a full total-cost-of-ownership picture that a fuel-only comparison cannot capture.

Frequently asked questions