If you provide a company car to a director, you must report the benefit on a P11D form. That is true even if the director pays for all the fuel themselves. The car itself is a taxable benefit regardless of who fills the tank.

The question many directors and their accountants face is whether the fuel benefit charge applies. And that depends entirely on who pays for private fuel. If the director covers every litre of private fuel personally, and the company pays for nothing, the fuel benefit charge is zero. But you still report the car benefit.

This distinction trips people up. Let me walk through the rules, the numbers, and the practical steps so you get it right.

The Core Distinction: Car Benefit vs Fuel Benefit

A company car generates two separate taxable benefits on a P11D. The first is the car benefit itself, based on the car's list price and its CO2 emissions. The second is the fuel benefit, based on a fixed figure (the car fuel multiplier) multiplied by the same CO2 percentage used for the car benefit.

These two benefits are independent. The car benefit applies whenever a director has a company car available for private use. The fuel benefit only applies if the company pays for any private fuel. "Private fuel" means any fuel not used for business travel.

So if the director pays for all fuel themselves, the fuel benefit charge drops to nil. But the car benefit remains reportable.

Take a concrete example. A director in Bristol runs a marketing consultancy through their limited company. The company provides a Tesla Model 3 with a list price of £48,000. The CO2 emissions are 0g/km, so the appropriate percentage for 2025/26 is 2%. The car benefit is £48,000 × 2% = £960. That goes on the P11D regardless of who pays for fuel.

The fuel benefit would be £27,800 (the car fuel multiplier for 2025/26) × 2% = £556. But if the director pays for all fuel personally, the fuel benefit is zero. The P11D shows £960 for the car and nothing for fuel.

What Counts as "Paying for All Fuel"

HMRC is specific about what this means. The director must pay for all fuel used in the car. Not just private fuel. All of it. If the company reimburses the director for any business fuel, that counts as the company paying for fuel. And if the company pays for any private fuel, the full fuel benefit charge applies.

There is no partial relief. If the company pays for one tank of private fuel in the year, the entire fuel benefit charge is triggered. The full £27,800 × appropriate percentage applies, with no reduction for the fuel the director paid themselves.

This is the trap. A director might think "I pay for most fuel, the company only paid for a couple of business fill-ups." That couple of fill-ups triggers the full fuel benefit charge. The director ends up paying tax on a benefit they barely used.

The Practical Solution: A Fuel Card or Company Account

If the company wants to pay for business fuel only, the cleanest approach is a dedicated company fuel card or a separate company credit card used only for fuel. The director then keeps a detailed mileage log showing business miles. At the end of each month, the director repays the company for the private fuel element.

The repayment must be at the advisory fuel rate (AFR) published by HMRC. For example, if the AFR for the car is 14p per mile and the director drives 500 private miles in a month, they repay the company 500 × 14p = £70. That repayment removes the private fuel from the company's cost, and the fuel benefit charge is avoided.

If the director simply pays for all fuel themselves and claims no reimbursement from the company, that is the simplest route. No fuel benefit. No P11D entry for fuel. Just the car benefit.

What Goes on the P11D When the Director Pays for All Fuel

The P11D form has separate boxes for the car benefit and the fuel benefit. When the director pays for all fuel, you complete the car benefit section as normal. Box 9F (car benefit) shows the calculated amount. Box 9G (fuel benefit) is left blank or entered as zero.

You still need to provide the car's details: make, model, registration, CO2 emissions, list price, and the date it was first registered. These go in the car section of the P11D.

The P11D must be filed with HMRC by 6 July following the end of the tax year. So for the 2025/26 tax year, the deadline is 6 July 2026. You also need to give the director a copy of their P11D by the same date.

Class 1A National Insurance is due on the car benefit (and the fuel benefit if it applies). The rate for 2025/26 is 13.8%. This is paid to HMRC by 19 July (or 22 July if paying electronically) following the tax year end.

What If the Director Uses a Personal Car for Business Instead?

If the director owns their own car and uses it for business, the company can pay them a mileage allowance. HMRC's approved mileage allowance payment (AMAP) rates are 45p per mile for the first 10,000 business miles and 25p per mile thereafter. These payments are tax-free to the director and deductible for the company.

No P11D is needed for mileage payments that stay within the AMAP rates. If the company pays more than the AMAP rate, the excess is a taxable benefit and must be reported on a P11D.

This is often simpler than a company car arrangement, especially for directors who do few business miles. But the company car has advantages too, particularly for higher-rate taxpayers who would get more tax relief on the benefit.

How the Car Benefit Is Valued

The car benefit calculation uses the car's list price (including VAT, delivery fees, and optional extras) and the appropriate percentage based on CO2 emissions. For 2025/26, the percentages range from 2% for zero-emission cars to 37% for high-emission petrol and diesel cars.

For electric cars, the percentage is 2% for 2025/26. This makes electric company cars extremely tax-efficient. A £60,000 electric car generates a car benefit of just £1,200. At the basic rate of income tax, that costs the director £240 in tax. At the higher rate, £480.

Compare that to a diesel car with CO2 emissions of 150g/km. The appropriate percentage might be 35%. A £30,000 diesel car generates a benefit of £10,500. The tax cost at higher rate is £4,200.

If the director pays for all fuel, the fuel benefit is avoided in both cases. But the car benefit still applies, and it can be significant for high-emission vehicles.

What About Private Fuel Reimbursement?

Some directors prefer to have the company pay for all fuel and then reimburse the company for private fuel. This is a valid approach, but it must be done properly.

The director must reimburse the company for the cost of private fuel, not at a flat rate. HMRC accepts reimbursement at the advisory fuel rate per mile for private miles. The director must keep a mileage log to separate business from private miles.

If the reimbursement is made before the P11D is filed, and it covers all private fuel costs, the fuel benefit charge is avoided. If the reimbursement is made after the P11D deadline, the fuel benefit charge applies for that year, and the reimbursement is treated separately.

This is where many directors get caught out. They intend to reimburse the company, but the paperwork is not done in time. The fuel benefit charge is triggered, and the director pays tax on a benefit they effectively paid for themselves.

What the P11D Means for the Director's Personal Tax

The car benefit (and any fuel benefit) shown on the P11D is added to the director's taxable income for the year. HMRC adjusts the director's tax code to collect the extra tax through PAYE, or the director declares the benefit on their self assessment return.

For a higher-rate taxpayer, a £5,000 car benefit costs £2,000 in extra income tax. A £10,000 car benefit costs £4,000. The tax is payable whether or not the director pays for fuel themselves.

This is why the decision to take a company car should factor in the full tax cost, not just the fuel element. A director who pays for all fuel saves the fuel benefit tax but still pays tax on the car benefit.

Common Mistakes to Avoid

The most common mistake is assuming that if the director pays for fuel, no P11D is needed at all. That is wrong. The P11D is still required for the car benefit.

The second most common mistake is the company paying for some fuel and the director paying for the rest, with no reimbursement. That triggers the full fuel benefit charge. There is no apportionment.

The third mistake is failing to file the P11D by 6 July. Late filing penalties apply: £100 per 50 employees per month for the first month, then increasing. For a single-director company, the penalty is £100 per month per P11D not filed.

If you are unsure whether your current arrangement triggers the fuel benefit charge, check your records. Who pays the fuel bills? Who reimburses whom? If the answer is not clear, it is worth reviewing with an accountant.

As ICAEW qualified accountants, we see these issues regularly. A quick review of your mileage records and fuel payment method can save significant tax.

Practical Steps to Get It Right

If you want the director to pay for all fuel and avoid the fuel benefit charge, follow these steps:

  • Ensure the company never pays for fuel directly. No company fuel card, no company credit card used for fuel, no reimbursement to the director for fuel costs.
  • The director pays for all fuel from their personal account. They keep receipts for business miles if they want to claim mileage from the company (but that would then trigger the fuel benefit rules).
  • If the director wants the company to pay for business fuel, set up a separate fuel card and have the director repay the company for private fuel at the advisory fuel rate. Do this monthly, before the P11D is filed.
  • File the P11D by 6 July each year, showing the car benefit only. Leave the fuel benefit box blank or enter zero.
  • Pay the Class 1A NIC on the car benefit by 19 July (or 22 July electronically).

If you are considering a company car for a director and want to understand the full tax implications, speak to your accountant. The decision involves corporation tax relief, personal tax, NIC, and the practicalities of fuel payment. It is not just about the P11D.

For more guidance on PAYE and payroll reporting, including P11D requirements, see our dedicated resources. If you need to review your current company car arrangements, contact us to discuss your specific situation.