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HoldingCost

EV savings calculator

Compare running an electric vehicle against a petrol one — fuel savings, total cost over time, and payback on the EV price premium.

Calculator vehicles

Logic updated April 2026

This calculator compares the running cost of an electric vehicle against an equivalent petrol vehicle and shows how long the fuel saving takes to pay back any difference in purchase price. Electric vehicles cost more upfront in most segments but cost less to run — the question is how many years of running savings it takes to break even.

How this is calculated

Formula 

annualPetrolCost = km × L100km / 100 × pricePerLitre ; annualElectricityCost = km × kWhPer100km / 100 × pricePerKwh ; payback = (evPrice − petrolPrice) / annualSaving

Step-by-step

  1. Calculate annual petrol cost: annual km × consumption per 100km ÷ 100 × fuel price per litre
  2. Calculate annual electricity cost: annual km × kWh per 100km ÷ 100 × electricity price per kWh
  3. Annual fuel saving = petrol cost − electricity cost
  4. Multiply annual saving by the comparison years to get total fuel saving over the period
  5. Calculate the purchase price premium: EV price − petrol price
  6. Payback years = price premium ÷ annual saving (negative when the EV costs less than the petrol equivalent)
Rounding mode
ROUND_HALF_UP
Precision
20-digit internal precision (Decimal.js), rounded to 2 decimal places for display
Logic last reviewed

Assumptions & limitations

What this calculator assumes

  • Petrol consumption and fuel price remain constant across the comparison period
  • EV energy consumption and electricity price remain constant across the comparison period
  • Annual km is driven at a consistent rate
  • Payback is calculated as purchase price difference divided by annual fuel saving
  • Maintenance and insurance differences are not modelled

What this calculator doesn’t account for

  • Does not include EV-specific government incentives, rebates, or import duty differences
  • Does not model the real-world impact of public fast-charging premiums vs home charging
  • Does not include battery degradation over very long ownership horizons
  • Does not model maintenance differences (EVs typically have lower servicing costs)
  • Does not factor in time-of-use electricity rates that can dramatically lower charging costs
  • Does not account for residual value differences between EVs and petrol cars

Worked example

A buyer compares a $50,000 EV vs an equivalent $42,000 petrol car driving 15,000 km/year over 8 years. Petrol consumes 7L/100km at $1.80/L; EV consumes 18 kWh/100km at $0.30/kWh.

Input Value
Petrol price / consumption $1.80/L / 7L/100km
Electricity price / consumption $0.30/kWh / 18 kWh/100km
Annual km 15,000
EV price / petrol price $50,000 / $42,000
Comparison years 8

Annual petrol cost: $1,890 — Annual electricity cost: $810 — Annual saving: $1,080 — Payback: ~7.4 years

Petrol: 15,000 × 7 ÷ 100 × $1.80 = $1,890/year. Electricity: 15,000 × 18 ÷ 100 × $0.30 = $810/year. Saving = $1,080/year. The $8,000 EV premium ÷ $1,080/year = 7.4 years to break even on fuel alone. Over 8 years the running saving is $8,640 — just covering the premium. Add maintenance savings (EVs typically save $300–600/year on servicing) and the break-even moves earlier.

Frequently asked questions

How much cheaper is an EV to run?

On home electricity, an EV typically costs 30–50% of an equivalent petrol car per kilometre. At $0.30/kWh, charging an EV consuming 18 kWh/100km costs about $5.40 per 100km. The same distance in a 7L/100km petrol car at $1.80/L costs $12.60. The fuel saving per kilometre is roughly $0.07 — over 15,000 km a year, that's around $1,000 a year.

Home charging vs public charging costs?

Home charging at off-peak rates is typically the cheapest option, often $0.10–$0.30 per kWh depending on jurisdiction. Public fast charging is much more expensive — often $0.50–$0.80 per kWh — and erodes most of the savings. Most EV owners do 80–90% of charging at home; if you can't, the running-cost case for an EV weakens substantially.

Do EVs have lower maintenance costs?

Generally yes — fewer moving parts (no engine oil changes, fewer brake replacements due to regenerative braking, no transmission service), but battery replacement after 8–15 years is a significant potential cost most petrol cars don't face. This calculator doesn't include maintenance — pair it with the total ownership cost calculator to layer that on.

How long until an EV pays for itself?

Depends on three things: the price premium over the petrol equivalent, your annual kilometres, and the spread between your fuel and electricity costs. Typical scenarios produce payback periods of 4–10 years. Higher annual kilometres shorten payback; significant government incentives can shorten it further by reducing the upfront premium. Below 8,000 km/year it's hard to make payback work on running costs alone.

What about charging time and convenience?

This calculator only models cost — it doesn't capture convenience trade-offs. Home charging is typically more convenient than petrol stops for daily use; long road trips currently favour petrol cars due to faster refuelling. The convenience picture varies by your driving pattern and local charging infrastructure — factor that in alongside the dollar payback figure.

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