Diesel Company Car Tax — £30,000 List Price
£25,000 salary · 33% BIK rate · England & Wales 2025-26
Company car BIK tax breakdown — 2025-26
| Car list price | £30,000 |
| BIK percentage (Diesel) | 33% |
| Taxable BIK value | £9,900 |
| Gross salary | £25,000 |
| Total taxable income (salary + BIK) | £34,900 |
| Income Tax on BIK | £1,980/year |
| National Insurance on BIK | £792/year |
| Total annual BIK tax cost | £2,772/year |
| Monthly BIK tax cost | £231/month |
BIK value = £30,000 × 33% = £9,900. 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) | £231 |
| Typical private car lease (comparable) | £150–£200 |
| EV alternative at 3% BIK (same list price) | £21/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.
Diesel company car tax on £25,000 salary — explained
With a £30,000 Diesel on a £25,000 salary, HMRC applies the 33% BIK rate to calculate a benefit in kind value of £9,900 per year. This amount is added to your gross salary, bringing your total taxable income to £34,900.
The additional Income Tax on this BIK is £1,980 per year (£231/month equivalent). You also pay National Insurance of £792 per year on the BIK value. Combined, the company car costs you £2,772 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 £231/month tax cost.
Frequently asked questions
How much company car tax do I pay on a £30,000 Diesel on a £25,000 salary?
On a £25,000 salary, a £30,000 list price Diesel with a 33% BIK rate creates a benefit in kind value of £9,900 per year. This adds £1,980 in Income Tax and £792 in National Insurance — a total of £2,772 per year (£231 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 £9,900, adding £2,772 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 (£30,000 list, £25,000 salary), the monthly BIK cost is £231.
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.
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