Company Car Benefit-in-Kind (BIK) Tax Calculator (UK)

Enter Calculation

Car P11D List Price (£)

Appropriate CO₂/BIK Percentage (%)

Your Income Tax Rate Basic rate (20%) Higher rate (40%) Additional rate (45%)

Results

Annual Company Car Tax

£1,500

payable per year

Taxable Benefit (BIK value)	£7,500
Monthly Tax	£125

What is the Company Car BIK Tax Calculator?

This calculator applies to the United Kingdom. If your employer provides a car that you can use privately, HMRC treats it as a taxable "benefit in kind" (BIK). This tool estimates how much income tax you will pay on that benefit each year and each month. Figures are based on HMRC's standard approach where the taxable benefit equals the car's P11D price multiplied by its appropriate CO₂ percentage.

How to use it

Enter three values:

P11D list price – the manufacturer's list price including VAT, delivery and most factory options (but excluding road tax and first-registration fee). CO₂/BIK percentage – the "appropriate percentage" for your car's CO₂ emissions and fuel type, taken from HMRC's published bands (0%–37%). Electric cars sit at the very low end; high-emission petrol/diesel cars approach 37%. Income tax rate – your highest marginal band: 20% basic, 40% higher or 45% additional.

The formula explained

First the taxable benefit is calculated: $$\text{BIK} = \text{P11D} \times \frac{\text{CO}_2\,\%}{100}$$ This is the cash-equivalent value of the perk. Your tax is then simply that benefit taxed at your marginal rate: $$\text{Tax} = \text{BIK} \times \frac{\text{Rate}\,\%}{100}$$ The monthly figure divides the annual tax by 12.

How the BIK tax is built from P11D value, CO₂ band and income tax rate.

Worked example

A car with a P11D price of £30,000 and a 25% CO₂ percentage has a taxable benefit of $$£30{,}000 \times 0.25 = £7{,}500$$ A higher-rate (40%) taxpayer pays $$£7{,}500 \times 0.40 = £3{,}000 \text{ per year}$$ or \(£250\) per month.

Lower CO₂ emissions mean a lower BIK percentage and less annual tax.

FAQ

Where do I find the CO₂ percentage? HMRC publishes annual benefit-in-kind percentage tables by CO₂ band and fuel type; your car's V5C and the manufacturer state the official CO₂ figure.

Does this include fuel benefit? No. If your employer also pays for private fuel, a separate fuel-benefit charge applies and is not included here.

Are electric cars cheaper? Yes — fully electric cars have a very low appropriate percentage, so the taxable benefit and resulting tax are dramatically lower than for a comparable petrol or diesel car.