EV vs Petrol Company Car Calculator
Compare company car tax and running costs between electric vehicles and traditional petrol or diesel cars.
Electric Vehicle
Petrol Vehicle
Common Settings
Why EV Company Cars Are So Much Cheaper Right Now
The Benefit-in-Kind (BiK) tax rate on electric company cars is 2% for 2025/26, rising to 3% in 2026/27 and 4% in 2027/28. A petrol car emitting 140 g/km of CO2 sits at around 33% BiK. On a £35,000 car, that is the difference between £700 of taxable benefit (EV) and £11,550 (petrol). For a 40% taxpayer, that converts to £280 a year in tax for the EV vs £4,620 for the petrol, a £4,340 annual saving before fuel even enters the picture.
The calculator pulls all this together: BiK tax for both cars at your tax rate, fuel cost across your annual mileage, and the side-by-side annual and 3-year totals. The headline saving is rarely small. For most company car drivers in 2026, an EV beats petrol by £3,000 to £6,000 a year on total cost, which makes the choice straightforward unless your usage genuinely does not work for an EV.
When the EV Numbers Stop Working
The model assumes home charging at around 28p per kWh, or off-peak rates of 7p to 10p per kWh. If you cannot charge at home (street parker, flat without a wallbox, no workplace charging), the picture changes. Public rapid charging at 80p per kWh on 12,000 miles a year costs around £2,750, vs £960 at home rates and roughly £1,800 in petrol for a 45 mpg saloon. The EV loses its fuel-cost advantage and you keep only the BiK saving.
Long-distance work also matters. A 25,000-mile-a-year sales rep doing daily 200-mile trips needs charging stops every 150 to 200 miles, and the cost difference vs a frugal diesel narrows further. The calculator lets you set realistic miles per kWh (typically 3.0 to 4.0 in mixed UK conditions) and electricity cost so you can stress-test the assumption against your actual driving.
The 3-Year Total Is the Real Number
Company cars are usually run for 3 to 4 years. Over that horizon, a typical comparison looks like this: an EV at £35,000 P11D, 2% BiK rising over the term, charged mostly at home, returning roughly £4,000 per year of tax + fuel. A petrol at £28,000 P11D, 33% BiK, returning around £8,500 per year. The 3-year totals come out to roughly £12,000 vs £25,500, a £13,500 saving over three years.
That margin shrinks if BiK rates rise faster than expected (the government has signalled this through 2030), if fuel prices drop sharply, or if your real-world EV efficiency is worse than headline figures. The [salary sacrifice car calculator](/salary-sacrifice-car-calculator) shows how the same EV looks under salary sacrifice rather than traditional company car arrangements; for many employees the salary sacrifice route is even better.
Frequently Asked Questions
What is the EV BiK rate for 2026/27?
3% for fully electric vehicles in 2026/27, rising to 4% in 2027/28 and 5% in 2028/29. Even at 5%, an EV is dramatically cheaper as a company car than a petrol equivalent at 25 to 35% BiK. The advantage shrinks but does not disappear, and for company cars taken on now, the rate locks in for the duration of the lease in most cases.
How does the calculator estimate EV fuel cost?
Annual mileage divided by miles per kWh, multiplied by your electricity cost. Default values are 3.5 miles per kWh (mixed driving for a typical mid-size EV) and 28p per kWh (standard UK home rate). Set your real-world figures to get an accurate comparison. Off-peak overnight rates of 7p to 10p make EVs roughly six times cheaper to fuel than a 45 mpg petrol; standard daytime rates make them around three times cheaper.
Does the comparison include road tax?
Not currently. EVs paid no Vehicle Excise Duty until April 2025; from April 2025 they pay the standard rate (£190 in 2025/26) plus a £390 'expensive car supplement' for cars with a list price over £40,000. Add £190 to £580 a year to the petrol car to make the comparison apples-to-apples; it does not change the conclusion much because the BiK saving still dwarfs VED.
What if the company pays for fuel?
If your employer reimburses fuel, the picture changes because petrol fuel benefit is also taxed (using a fixed multiplier based on CO2 emissions). EV electricity reimbursement is not currently classed as a fuel benefit if claimed under HMRC's Approved Mileage Allowance Payments at the special EV rate. This is an area where the calculator's defaults assume you pay your own fuel; if your employer reimburses, the saving is even larger because the petrol fuel benefit tax is removed too.
Can I get a salary sacrifice EV?
Yes, this is a popular route. Through a salary sacrifice scheme, the lease cost comes out of your gross salary (saving income tax and National Insurance) and you only pay the small BiK charge. Effective monthly cost is often 30 to 40% lower than a personal lease. Check whether your employer participates in a scheme like Octopus Electric Vehicles, Tusker, or Loveelectric.
Related Tools
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Compare the true cost of ownership between petrol/diesel and electric vehicles over 5-10 years.