Benefit in Kind (P11D) Tax Calculator | NoMoreJanuary
Free calculator for the tax on company cars, private medical insurance, and low-interest loans from your employer. Get your BIK tax in seconds.
If your employer provides benefits like a company car,private medical insurance, or a low-interest loan, you owe income tax on the "cash equivalent" of those benefits. The amount depends on the benefit type, your tax bracket, and — for company cars — the vehicle's CO2 emissions and fuel type.
This calculator handles all three benefit types using current HMRC BIK rate tables and official interest rates. Choose a tab, enter your details, and get the annual and monthly tax you'll pay on each benefit.
Frequently Asked Questions
What is a P11D?
A P11D is the form your employer files with HMRC to report the value of benefits they've given you during the tax year — things like a company car, private medical insurance, or a low-interest loan. The "cash equivalent" shown on the P11D is the taxable value of those benefits, and you pay income tax on it at your marginal rate.
How is company car benefit in kind calculated?
The taxable benefit for a company car is based on the car's list price (P11D value) multiplied by a BIK percentage rate. The rate depends on the car's CO2 emissions and fuel type — lower emissions mean a lower rate. Diesel cars that aren't RDE2-compliant get a 4% supplement. Fully electric cars have the lowest rate (2% in 2024-25, 3% in 2025-26).
Do I need to declare benefit in kind on my Self Assessment?
Yes. If you receive benefits in kind from your employer, you need to declare them on your Self Assessment tax return. They go in the "Employment" section under "benefits and expenses." The cash equivalent from your P11D is added to your income and taxed at your marginal rate.
Are loans from my employer always taxable?
No. Loans from your employer with a maximum balance under £10,000 at any point in the tax year are exempt from benefit in kind tax. For loans over £10,000, the taxable benefit is the difference between the official interest rate and the rate you actually pay, applied to the maximum balance.