A company car can look like a generous workplace benefit, but the real cost is not the monthly lease figure shown on the scheme portal. For employees, the key number is usually the Benefit in Kind value added to taxable income. That is why a practical company car tax guide UK drivers can use should start with the tax calculation, not the badge on the bonnet.
A higher-priced electric car may create a much smaller tax bill than a cheaper petrol model, while optional extras can increase the taxable value even when the employer receives a discount. Before choosing, compare the total monthly impact: any salary given up, the company car tax, private fuel or charging costs, and what the scheme includes.
What company car tax actually charges
Company car tax applies when an employer provides a car that is available for private use. Private use includes commuting between home and a permanent workplace. HMRC instead calculates a cash value for the benefit, commonly called the Benefit in Kind or BIK value.
The broad calculation is straightforward. Take the car’s taxable list price, apply the appropriate BIK percentage, and then apply your marginal Income Tax rate. The annual taxable benefit is normally the car’s P11D value multiplied by its BIK rate. Your tax cost is that benefit multiplied by the relevant 20%, 40% or 45% rate.
The P11D value is not the discounted price
The starting figure is normally the manufacturer’s UK list price when new, including VAT and taxable accessories. A heavily discounted premium model can therefore still produce a sizeable benefit in kind car tax bill.
Qualifying employee capital contributions can reduce the price used in the calculation, subject to HMRC rules and a maximum deduction of £5,000. Required payments specifically for private use may also reduce the taxable benefit. Ask the provider how each payroll deduction is treated rather than assuming every contribution lowers BIK.
BIK rates 2026: what matters for your choice
For the 2026/27 tax year, running from 6 April 2026 to 5 April 2027, the percentage is driven mainly by official CO2 emissions, fuel type and, for certain plug-in hybrids, electric-only range. A zero-emission company car has a 4% BIK rate in 2026/27.
Plug-in hybrids emitting 1 to 50g/km are placed into bands according to electric range. The 2026/27 rate is 4% for at least 130 miles, 7% for 70 to 129 miles, 10% for 40 to 69 miles, 14% for 30 to 39 miles and 16% for less than 30 miles. Above 50g/km, percentages rise through the table to a maximum of 37%.
Most modern diesel cars that meet the required Real Driving Emissions standard avoid the diesel supplement. A diesel that does not qualify can attract four extra percentage points, still capped at 37%. Check the exact CO2 figure and certification for the specific derivative because versions of the same model can sit in different bands.
A real-world monthly tax comparison
Imagine an employee choosing between two cars for a full tax year. Car A is an electric model with a £40,000 P11D value. At 4%, its taxable benefit is £1,600. A 20% taxpayer would pay £320 a year, or about £26.67 a month. A 40% taxpayer would pay £640 a year, or about £53.33 a month.
Car B is a £32,000 petrol model emitting 102g/km. The 2026/27 rate for 100 to 104g/km is 26%, creating a taxable benefit of £8,320. That means about £1,664 a year for a 20% taxpayer, or £138.67 a month. For a 40% taxpayer, it becomes £3,328 a year, or about £277.33 a month.
The petrol car is £8,000 cheaper on list price, yet its company car tax is more than five times higher in this example. This is the central lesson when comparing a company car scheme UK employers offer: price matters, but the interaction between price and BIK percentage matters more.
Costs outside the basic BIK figure
Private fuel can create a second charge
If an employer provides petrol or diesel for private journeys and the employee does not repay the full private-use cost under the rules, a separate fuel benefit can arise. For 2026/27, the multiplier is £29,200, multiplied by the same percentage used for the car. The charge is formula-based, so it can be poor value for someone who uses little private fuel.
Electricity is treated differently and does not fall within the traditional car fuel benefit charge for a fully electric company car. Check whether workplace charging, reimbursement or a home charger is included.
Salary sacrifice affects take-home pay
Many schemes require employees to give up part of their salary. Compare the net reduction in take-home pay plus BIK tax against the cost of running a privately owned car. Also consider possible effects on pension contributions, mortgage affordability evidence and earnings-related workplace benefits.
Accessories can be surprisingly costly
Larger wheels, premium paint, upgraded trim and technology packs may increase the P11D value. Request a tax calculation for the exact specification, not merely the base model shown in advertising.
How to compare cars before signing
Ask for the P11D value, official CO2 emissions, electric range where relevant, BIK percentage for each tax year in the agreement, and an estimated tax cost based on your tax band. Then add any employee rental, insurance excess, mileage charges, early termination terms and expected private fuel or electricity spending.
It is sensible to model a change in circumstances. A pay rise could move part of the benefit into a higher tax band, while leaving the employer may trigger scheme charges. Do not rely on one headline monthly figure.
Useful related reading includes electric car running costs, leasing versus buying, and calculating the total cost of car ownership.
Frequently asked questions
How is company car tax collected?
It is commonly collected through PAYE by adjusting your tax code or through employer payroll. Check your Personal Tax Account and report changes when you receive, change or return a company car.
Does company car tax use the purchase price?
Usually no. The calculation normally starts with the official list price and taxable accessories, not the discounted price paid by the employer.
Are electric company cars tax-free?
No. A zero-emission company car has a low BIK percentage but is still taxable. For 2026/27, the rate is 4%, so list price and tax band still affect the cost.
Can I avoid tax by using the car only for commuting?
No. Ordinary commuting counts as private use. The car generally must not be available for private use, with a genuine restriction in practice, for the benefit charge not to arise.
Choose by after-tax cost, not list price
The financially sensible company car is not automatically the cheapest vehicle or the model with the lowest salary deduction. Start with the exact P11D value and 2026/27 BIK percentage, calculate the tax at your marginal rate, and then add every other monthly cost. That turns a confusing workplace benefit into a comparison you can make with confidence.
