How company car tax is calculated: benefit-in-kind and P11D explained

Published: 07 January 2025

► How company car tax works
► Benefit-in-kind (BIK) tax explained
► Why CO2 emissions will cost you more

Company cars, whether sold through fleets or businesses, now account for a far greater share of new car sales than those to private individuals, and this percentage has only kept increasing in recent years. 

As a result, it makes it an important sector that car manufacturers target, especially for electric cars, which are considerably cheaper to run as company cars. Though a company car is often a perk of a job, it’s by no means free as there’s a tax implication on it, which can prove significant depending on the car.

Let’s look at how company car tax is calculated, how much it costs and any changes on the horizon. All of this will help you if you’re looking for a company car andl help you to make an informed financial decision.

What is benefit-in-kind (BIK) tax? 

A company car is seen as a benefit-in-kind (BIK) by HMRC since it’s usually supplied as a perk in addition to an employee’s salary. This means that if you use a company car, you are required to pay annual tax on it, in the same way that you would if your employer gave you free health insurance.

BIK tax rates change most years and the planned rates for future years are known well in advance. In the UK, company car tax is decided by a vehicle’s emissions, its value and your personal income tax rate.

Every car has a BIK tax banding percentage, which is based on the CO2 emissions it produces. As most company cars are kept for several years, it’s worth looking at future years. For example, all plug-in hybrids will have a steep increase in company car tax in the 2028/29 financial year. The bandings are as follows.

CO2 (g/km)Electric range (miles)2024/25 (%)2025/26 (%)2026/27 (%)2027/28 (%)2028/29 (%)2029/30 (%)
0N/A234579
1-50> 13023451819
1-5070 to 12956781819
1-5040 to 698910111819
1-5030 to 39121314151819
1-50< 30141516171919
51 to 54151617181920
55 to 59161718192021
60 to 64171819202122
65 to 69181920212223
70 to 74192021212223
75 to 79202121212223
80 to 84212222222324
85 to 89222323232425
90 to 94232424242526
95 to 99242525252627
100 to 104252626262728
105 to 109262727272829
110 to 114272828282930
115 to 119282929293031
120 to 124293030303132
125 to 129303131313233
130 to 134313232323334
135 to 139323333333435
140 to 144333434343536
145 to 149343535353637
150 to 154353636363738
155 to 159363737373839
160+373737373839

What is a P11D value? 

A P11D value is used to calculate company car tax, and is an important number for this reason. 

​​The P11D value is the total value of a car when it was new, including the list price, optional extras (including paint colours and different wheels), VAT and delivery charges from the manufacturer. However, it does not include the DVLA first registration fee or annual road tax. It therefore tends to look slightly different to the actual on-the-road price quoted by dealers and by CAR. 

How is company car tax calculated?

The main factor in working out how much company car tax you’ll pay depends on a vehicle’s CO2 emissions. The cleaner it is, the less you’ll pay, which is why it generally favours electric vehicles and plug-in hybrid models, although there is some uncertainty surrounding PHEVs, as we’ll explore in a later section. If you’re looking at a plug-in hybrid as a company car, look at its quoted electric range as this will also influence what you’ll pay. 

To calculate the company car (BIK) tax, multiply the P11D value by the BIK percentage figure, and then multiply that figure by your personal tax band (20 or 40 per cent). This figure will give you the annual amount of BIK you need to pay, so divide it by 12 to see the monthly outgoing. 

Here are two examples of company car tax for the 2025/26 financial year.

Car: Tesla Model 3 RWD
P11D value: £39,935
CO2 emissions: 0g/km
Company car tax band: 3%
Taxable benefit-in-kind: £1,198.05 (3% of the P11D list price)
Driver BIK tax bill: £239.61 per annum (lower rate taxpayer at 20% tax), £479.22 (higher rate taxpayer at 40% tax)

Car: Volkswagen Golf Style 1.5 eTSI
P11D value: £30,400
CO2 emissions: 121g/km
Company car tax band: 30%
Taxable benefit-in-kind: £9,120 (30% of the P11D list price)
Driver BIK tax bill: £1,824 per annum (lower rate taxpayer at 20% tax), £3,648 (higher rate taxpayer at 40% tax)

If you look at the difference between what you’ll pay on an electric car and a run-of-the-mill petrol hatchback like a Volkswagen Golf, you’ll get an idea of why electric cars are proving so popular to company car drivers because of the cost savings on offer.

Big changes coming for plug-in hybrid cars and BIK

Alongside electric cars, plug-in hybrid vehicles (PHEVs) have proven popular with company car drivers owing to their cheaper BIK as a result of their lower claimed CO2 emissions. However, many PHEVs now face a potentially steep increase in BIK rates because of a change in how emissions tests are carried out on them.

Known as Euro 6e-bis, the revised emissions test applies to all newly launched PHEVs from January 1, 2025, and will apply to all new models by the end of 2025. The more rigorous test now involves measuring a vehicle’s emissions for a greater distance when a PHEV’s battery is empty, and therefore when they’re least efficient.

BMW X1

To illustrate the difference the changes will make, the International Council on Clean Transport (ICCT) analysed the effect on a BMW X1 plug-in hybrid. Under the current testing model, this car has an official CO2 emission value of around 45g/km, but under the new tests, the emissions value will more than double to 96g/km. This will see the BIK rate increase from 8% to 24%, and will mean a significant increase in what you’ll pay in company car tax

Drivers who already have a PHEV as a company car will not be affected, but those ordering a new car could see a steep potential steep increase if the car is retested between the point of ordering and delivery. Fewer are likely to choose PHEVs as company cars as a result of these measures, either.

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