Useful next calculations
Rates and sources, 2026/27
Company-car cash equivalent is P11D list price × appropriate percentage. Zero-emission cars are 4% for 2026/27.
| Band or figure | Rate |
|---|---|
| Zero-emission appropriate % | 4% |
| Tax | cash equivalent × income-tax rate |
Source: GOV.UK — Tax on company cars. Source checked for 2026/27.
When to use this calculator
- When you need a fast estimate before making a bigger decision.
- When you want to compare a few scenarios using the same assumptions.
- When you need a clearer starting point before using a detailed quote or formal document.
- When you want to sanity-check a figure you have seen elsewhere.
A worked example
These are the example figures the calculator opens with.
| Input | Value |
|---|---|
| P11D / list price (£) | £35,000 |
| BIK percentage | 4 |
| Income tax rate (%) | 20% |
For those figures the calculator returns:
- Cash equivalent: £1,400.00
- Annual BIK tax: £280.00
- Monthly: £23.33
How to read your results
Annual BIK tax
Review this figure alongside your gross income so you can understand deductions before the tax year closes. It is a planning estimate, not a filed return.
Method & assumptions
UK company-car benefit-in-kind tax is the P11D list price multiplied by the appropriate BIK percentage, then taxed at your income-tax rate. For 2026/27 the appropriate percentage for a zero-emission car is 4%. Petrol and diesel percentages depend on CO2 and electric range; enter the official percentage from HMRC’s company-car table rather than guessing.
This tool does not add Class 1A employer NI, fuel benefit, vans, or private-use adjustments. Confirm the list price, accessories and the appropriate percentage with payroll. Source: GOV.UK tax on company cars.
Common mistakes
- Using optimistic assumptions without testing a more cautious scenario.
- Comparing outputs from different tools without checking that the inputs match.
- Treating the result as a final quote instead of a planning estimate.
- Rounding inputs too aggressively.
What to do next
- Try at least one more scenario so you can compare a realistic range.
- Use the related calculators below to cross-check the decision from another angle.
- Write down the key outputs from your best scenarios before you decide.
- If the result surprises you, change one input at a time to isolate the driver.