Diesel Company Car Tax — £40,000 List Price
£35,000 salary · 33% BIK rate · England & Wales 2025-26
Company car BIK tax breakdown — 2025-26
| Car list price | £40,000 |
| BIK percentage (Diesel) | 33% |
| Taxable BIK value | £13,200 |
| Gross salary | £35,000 |
| Total taxable income (salary + BIK) | £48,200 |
| Income Tax on BIK | £2,640/year |
| National Insurance on BIK | £1,056/year |
| Total annual BIK tax cost | £3,696/year |
| Monthly BIK tax cost | £308/month |
BIK value = £40,000 × 33% = £13,200. Tax calculated using 2025-26 England & Wales Income Tax and National Insurance rates.
Is this company car worth it?
Diesel company cars attract a 4% surcharge on top of the CO2-based rate, resulting in a 33% BIK for a typical diesel. The tax cost is among the highest of any fuel type. Carefully weigh this against any mileage or fuel savings before choosing a diesel company car.
| Scenario | Monthly cost |
|---|---|
| Company car BIK tax (this car) | £308 |
| Typical private car lease (comparable) | £200–£267 |
| EV alternative at 3% BIK (same list price) | £28/mo approx. |
Private lease estimates are approximate (list price ÷ 150–200). EV alternative uses 3% BIK rate at basic rate tax (20% IT + 8% NI). Actual figures depend on individual lease terms and tax position.
Personalised insights for this company car
On a £35,000 salary, the £3,696/year BIK charge consumes 10.6% of your gross income. For context, it would take 1.9 months of National Living Wage gross pay (£1,984/month) to cover this tax bill. A privately leased equivalent would cost around £74/month less than this company car, so the car is only worthwhile if you value the cover-all-costs convenience.
Diesel company car tax on £35,000 salary — explained
With a £40,000 Diesel on a £35,000 salary, HMRC applies the 33% BIK rate to calculate a benefit in kind value of £13,200 per year. This amount is added to your gross salary, bringing your total taxable income to £48,200.
The additional Income Tax on this BIK is £2,640 per year (£308/month equivalent). You also pay National Insurance of £1,056 per year on the BIK value. Combined, the company car costs you £3,696 per year in extra tax — deducted through PAYE each pay period.
Unlike salary, you do not receive cash for the BIK — the car is the benefit. The question is whether the car's value to you (private fuel, convenience, cost vs. personal leasing) exceeds the £308/month tax cost.
Put differently: this BIK charge is the equivalent of sacrificing £5,133 of gross salary — because at your marginal rate (28% combined (basic rate IT + NI)), that gross figure would deliver the same net hit as the £3,696/year BIK tax. It also equates to roughly 1.9 months of National Living Wage gross pay (£23,810/year in 2025-26). A privately leased equivalent would cost around £74/month less than this company car, so the car is only worthwhile if you value the cover-all-costs convenience. For many drivers of Diesel at 33% BIK, an EV salary sacrifice scheme or taking cash instead often wins on pure numbers.
Frequently asked questions
How much company car tax do I pay on a £40,000 Diesel on a £35,000 salary?
On a £35,000 salary, a £40,000 list price Diesel with a 33% BIK rate creates a benefit in kind value of £13,200 per year. This adds £2,640 in Income Tax and £1,056 in National Insurance — a total of £3,696 per year (£308 per month).
How is company car tax calculated?
HMRC calculates company car tax using: BIK value = list price × CO2-based percentage. The BIK value is added to your gross salary and taxed at your marginal Income Tax rate. You also pay National Insurance at 8% (or 2% above £50,270) on the BIK value. For this car, the 33% rate gives a BIK value of £13,200, adding £3,696 to your annual tax and NI bill.
Is a Diesel company car worth it?
Diesel company cars attract a 4% surcharge on top of the CO2-based rate, resulting in a 33% BIK for a typical diesel. The tax cost is among the highest of any fuel type. Carefully weigh this against any mileage or fuel savings before choosing a diesel company car. For this specific car (£40,000 list, £35,000 salary), the monthly BIK cost is £308.
Can I reduce company car tax?
Yes — the most effective way is to choose a lower-emission vehicle. Electric cars have a 3% BIK rate versus 29-37% for high-emission petrol/diesel. You can also make a capital contribution (up to £5,000) to reduce the list price used in the BIK calculation. Alternatively, returning the company car and taking additional salary or opting for an EV salary sacrifice scheme avoids company car tax entirely.
What is the monthly company car tax cost for a £40,000 Diesel?
The monthly BIK tax cost for a £40,000 Diesel on a £35,000 salary is £308/month. This breaks down as £2,640 Income Tax and £1,056 National Insurance annually, collected through PAYE. Over a typical 3-year company car contract, this amounts to approximately £11,088 in total BIK tax.
How does the £40,000 P11D value affect my take-home pay compared to a salary increase?
A company car does not increase your cash take-home pay — it adds £13,200 to your taxable income, costing you £3,696/year in extra tax. To match the car value in after-tax cash, your employer would need to increase your salary by roughly £13,200. Whether the car is worth more to you than that equivalent salary uplift depends on your personal use of the vehicle and whether you would otherwise pay for a private lease.