P11D is a form that is used in the United Kingdom to report the value of benefits in kind (BIK) that are provided to an employee by their employer. Benefits in kind are non-cash benefits that an employee receives in addition to their salary or wages, and they can include things like company cars, accommodation, and private medical insurance.

Employers are required to report the value of benefits in kind on a P11D form if the value of the benefits exceeds certain thresholds. The form must be submitted to HM Revenue and Customs (HMRC) by the 6th of July following the end of the tax year in which the benefits were provided.

If the value of the benefits in kind exceeds the employee's tax-free allowance, the employee may be required to pay tax on the excess. The tax on benefits in kind is calculated at the employee's marginal tax rate and is paid through the PAYE (Pay As You Earn) system.

If you are an employee in the UK and have received benefits in kind from your employer, it is important to understand your tax obligations and to ensure that you are correctly reporting the value of the benefits on your tax return. You may wish to seek advice from a tax professional or from HMRC if you have any questions or need help with your P11D form.