What is a P11D?▾
A P11D is a form that employers use to report benefits in kind (BIK) and expenses provided to employees. Common benefits include company cars, private medical insurance, gym memberships, and interest-free loans. The P11D must be submitted to HMRC by 6 July following the end of the tax year.
How is benefit in kind (BIK) tax calculated?▾
BIK tax is calculated by determining the cash equivalent value of the benefit, then taxing it at the employee’s marginal income tax rate. For example, if private medical insurance costs £1,200/year and you are a 40% taxpayer, the tax is £480. The employer also pays Class 1A NI at 15% on the BIK value.
How does company car BIK work?▾
Company car BIK is based on the car's list price multiplied by an appropriate percentage set by HMRC. Fully electric cars are charged at 4% for 2026/27. Cars emitting 1-50g/km are charged at 4% to 16% depending on their electric-only range, and from 51g/km the percentage starts at 17% and rises one point per 5g/km band to the 37% maximum at 155g/km. The 70-74 and 75-79g/km bands are both 21%, because the 2026/27 uplift was capped at 21% and applied only below 75g/km — bands from 75g/km up are frozen at their 2025/26 level until 5 April 2028. Diesel cars that do not meet the RDE2 standard add 4 percentage points, capped at 37%. For example, a car with a £35,000 list price and a 20% appropriate percentage creates a £7,000 annual BIK value.
What is the fuel benefit charge?▾
If your employer pays for private fuel in a company car, an additional fuel benefit charge applies. It is calculated by multiplying a fixed amount (£29,200 for 2026/27) by the same appropriate percentage as the car. For a car on a 20% appropriate percentage, the fuel benefit is £5,840. It often makes more sense to pay for private fuel yourself.
What is Class 1A National Insurance?▾
Class 1A NI is paid by the employer at 15% on the total value of all benefits in kind, up from 13.8% before 6 April 2025. This is in addition to the regular employer NI paid on salary. For £10,000 in total BIK, the employer pays £1,500 in Class 1A NI. It is due by 22 July (19 July if paying by post).
Is private medical insurance a taxable benefit?▾
Yes. The full cost of private medical insurance paid by your employer is a taxable benefit in kind. The BIK value is the premium paid. If your employer pays £1,500/year for your policy and you are a 40% taxpayer, you pay £600 in tax. Family cover has a higher BIK value than individual cover.
Are interest-free loans a taxable benefit?▾
Interest-free or low-interest loans from your employer are a taxable benefit if the total outstanding balance exceeds £10,000 at any point in the tax year. The BIK value is the difference between interest at HMRC's official rate (currently 2.25%) and any interest you actually pay.
When does business mileage create a taxable benefit?▾
Mileage reimbursed at or below the HMRC Approved Mileage Allowance Payment (AMAP) rates is not taxable and does not go on your P11D. For cars and vans the approved rates are 55p per mile for the first 10,000 business miles in the tax year and 25p per mile after that. A taxable benefit arises only on the excess where your employer pays more than the approved rate. If your employer pays 65p per mile and you drive 15,000 business miles, the approved amount is £6,750 and you were paid £9,750, so the taxable excess is £3,000. If your employer pays less than the approved rate there is no benefit at all — instead you can claim Mileage Allowance Relief on the shortfall, which is a deduction from your taxable income rather than an addition to it.
Can I salary sacrifice to reduce BIK?▾
Yes. Salary sacrifice arrangements for certain benefits (pension, childcare, cycle-to-work, ultra-low emission cars) can reduce your taxable income and BIK. However, since April 2017, most other salary sacrifice arrangements offer no tax advantage as the BIK is charged at the higher of the salary given up or the benefit value.
When do I need to submit a P11D?▾
Employers must submit P11D forms to HMRC by 6 July following the end of the tax year. P11D(b) forms (summarising Class 1A NI due) have the same deadline. Employees must receive a copy of their P11D by the same date. Late submissions attract penalties of £300 per form.