About the Company Car Tax (BIK) Calculator
If your employer gives you a car for private use, HMRC treats it as a taxable Benefit in Kind (BIK). The amount of tax you pay depends on the car's list price (P11D value), its CO2 emissions (which set a BIK percentage band), and your personal income tax rate. This calculator applies HMRC's 2026/27 BIK bands to estimate your annual company car tax.
How it works
- Your car's CO2 emissions determine a BIK percentage from HMRC's banded table (3% for zero-emission electric cars, rising with emissions up to a 37% cap).
- Taxable benefit value = P11D value × BIK%.
- Annual tax owed = taxable benefit value × your income tax rate (20%, 40% or 45%).
Assumptions and behaviour
- Uses HMRC's 2026/27 BIK band table for petrol and RDE2-compliant diesel cars, with a flat +4% surcharge (capped at 37%) if you mark the car as non-RDE2-compliant diesel.
- Plug-in hybrids (1-50 g/km) use a flat 6% approximation — the real HMRC rate for this band varies 6-19% depending on the car's electric-only range, which this simplified calculator doesn't ask for.
- Assumes the car is available for the full tax year with no employee capital contribution or private-use payment deducted.
Limitations
- Doesn't adjust for a part-year availability, employee capital contributions (up to £5,000 reduces the P11D value), or private fuel benefit (a separate charge).
- The 1-50 g/km plug-in hybrid band is simplified — check HMRC's exact table by electric range for a precise figure.
- Estimates only — not tax advice. Confirm with HMRC or your employer's payroll team.
Privacy
The calculation runs entirely in your browser. Nothing is uploaded or stored.
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