P11D Benefits Tax Calculator UK 2025

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.

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 13.8% on the BIK value.

Company car BIK is based on the car's list price multiplied by a percentage determined by the CO2 emissions. Electric cars have a 2% BIK rate, while petrol/diesel cars range from 8% to 37%. For example, a car with a £35,000 list price and 20% BIK rate creates a £7,000 annual BIK value.

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 (£27,800 for 2025/26) by the same BIK percentage as the car. For a 20% BIK car, the fuel benefit is £5,560. It often makes more sense to pay for private fuel yourself.

Class 1A NI is paid by the employer at 13.8% on the total value of all benefits in kind. This is in addition to the regular employer NI paid on salary. For £10,000 in total BIK, the employer pays £1,380 in Class 1A NI. It is due by 22 July (19 July if paying by post).

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.

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.

If your employer reimburses you for business mileage above the HMRC approved rates (45p for the first 10,000 miles, then 25p per mile), the excess is a taxable benefit. If your employer pays 50p per mile and you drive 15,000 business miles, the excess on the first 10,000 is 5p x 10,000 = £500, plus 25p x 5,000 = £1,250.

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.

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.