What is a P11D and which benefits are reportable?

A P11D is the HMRC form an employer files annually (by 6 July) to report each employee's taxable Benefits in Kind. Common reportable benefits include company cars and fuel, private medical insurance, gym membership, employer-provided living accommodation, interest-free loans above £10,000, and other non-cash perks. Cash bonuses run through PAYE so do not appear on the P11D - they are taxed at source. Benefits run through payroll ("payrolled" benefits) also bypass the P11D, but the underlying tax cost is identical.

How is the company car BIK calculated in 2026/27?

Company car BIK = P11D list price x appropriate percentage. The appropriate % depends on CO2 emissions: fully electric cars are 4% in 2026/27 (rising 1pp per year to 9% in 2029/30); plug-in hybrids 4-16% banded by electric-only range; petrol and hybrids scale from 17% at 51-54 g/km up to a 37% cap. Diesel cars not meeting RDE2 add a 4 percentage-point supplement (still capped at 37%). All 2021+ diesels typically meet RDE2 so avoid the supplement.

What is the fuel benefit charge for 2026/27?

If your employer pays for private fuel in a company car, HMRC charges you tax on a notional fuel benefit. The 2026/27 charge is calculated as your car's appropriate % multiplied by £28,200 (the published Fuel Benefit Charge multiplier; HMRC updates this annually with CPI). At 30% appropriate %, that is £8,460 added to your taxable income - £3,384 a year for a 40% taxpayer. For most employees this works out worse than paying for fuel yourself, so private fuel benefits are rarely worthwhile unless your private mileage is very high. Electric cars are exempt - HMRC does not treat electricity as fuel for P11D purposes.

How is private medical insurance taxed?

The full annual premium your employer pays for your private medical or dental cover (and any covered dependants) is the cash equivalent reported on your P11D. It is added to your taxable income for Income Tax at your marginal rate. A £1,500/year policy costs a 40% taxpayer £600/year in tax. Your employer also pays Class 1A National Insurance at 15% on the £1,500 - a £225 employer-side cost.

Who pays National Insurance on Benefits in Kind?

BIKs do not attract employee National Insurance under the standard P11D route - only the employer pays Class 1A NI at 15% (2026/27 rate, aligned with the main Class 1 Secondary rate from April 2025). This is one reason BIKs and especially salary-sacrifice EVs are tax-efficient: a £1,000 salary increase costs the employer 15% NI AND triggers 8% (or 2%) employee NI; the same £1,000 of BIK costs the employer only the 15% Class 1A and the employee nothing in NI.

Should I take a company car or a cash allowance?

It depends on three things: the appropriate %, your marginal tax rate, and what you would do with the cash alternative. For electric cars (4% in 2026/27) the BIK route is usually overwhelmingly cheaper than a cash allowance - a £50,000 EV costs a 40% taxpayer £800/year in tax versus £20,000+ a year if they took the cash and bought the same car post-tax. For petrol/diesel above ~120 g/km, the cash allowance often wins. Salary sacrifice on low-emission cars (under 75 g/km) is also exempt from the "optional remuneration arrangement" anti-avoidance rule, preserving the BIK route.

What is the difference between payrolled benefits and P11D?

Both produce the same Income Tax outcome - the difference is timing and administration. Payrolled benefits are taxed in real time through PAYE each pay period (no end-of-year P11D needed, employer must register before the tax year starts). P11D-reported benefits are taxed via a tax-code adjustment after HMRC processes the form, usually meaning a lower tax code for the following year. From April 2026 most BIKs will become mandatorily payrolled (HMRC has confirmed this is the direction of travel), with only a few exceptions like employer-provided accommodation continuing on P11D.

What happens to BIK when income hits the £100k personal-allowance taper?

Between £100,000 and £125,140 of adjusted net income, Personal Allowance is withdrawn at £1 for every £2 above £100k - producing a 60% effective marginal rate. BIKs add to adjusted net income, so a company car BIK that pushes you from £95k into the taper zone is taxed at 60% on the slice above £100k, not the 40% you might expect. The calculator handles this automatically by running the salary engine with and without the BIK and using the actual Income Tax delta.

£100,000 Company Car: UK P11D / BIK Tax 2026/27

A £100,000 P11D list price triggers very different Benefits in Kind tax depending on fuel type. An electric car at 4% appropriate percentage adds £4,000 to your taxable income - £1,600 of Income Tax for a 40% taxpayer. A petrol equivalent at 32% adds £32,000 - £14,200 in tax. Verified against HMRC 480 Appendix 2.

EV (4%), 40% taxpayer

£1,600

BIK £4,000 - per month £133

Petrol 130 g/km, 40% taxpayer

£14,200

BIK £32,000 - per month £1,183

Employer Class 1A (EV)

£600

15% of BIK - employer cost

How the BIK is calculated on £100,000

Take the P11D list price (list + options + VAT, less capital contribution up to £5,000): £100,000.
Multiply by the appropriate percentage from HMRC 480 Appendix 2: 4% for an EV, 32% for a 130 g/km petrol, 37% for non-RDE2 diesel at 150 g/km.
That gives the annual BIK amount, added to your taxable income as if it were extra salary.
Apply your marginal Income Tax rate (20% / 40% / 45% / 60% in the £100k taper) to get your annual tax cost.
Your employer pays Class 1A National Insurance at 15% on the same BIK amount - this is an employer cost only.

All 9 scenarios at £100,000

BIK amount, Income Tax cost, and employer Class 1A NI across three fuel profiles and three marginal-rate tiers. Adjust the values interactively on the main calculator.

Car	Taxpayer	Approp. %	BIK	Income Tax	Employer Class 1A
EV	20%	4%	£4,000	£800	£600
EV	40%	4%	£4,000	£1,600	£600
EV	45%	4%	£4,000	£1,800	£600
Petrol 130	20%	32%	£32,000	£8,746	£4,800
Petrol 130	40%	32%	£32,000	£14,200	£4,800
Petrol 130	45%	32%	£32,000	£14,400	£4,800
Diesel 150	20%	37%	£37,000	£10,746	£5,550
Diesel 150	40%	37%	£37,000	£17,200	£5,550
Diesel 150	45%	37%	£37,000	£16,650	£5,550

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Related calculators

P11D / BIK calculator - tune medical, fuel, accommodation alongside the car.
Company car tax calculator - drill into the CO2 scale and PHEV bands.
EV salary sacrifice - why a salary-sacrificed EV beats a cash allowance for most higher-rate taxpayers.
60% tax trap - what happens when a BIK pushes you into the £100k taper.

Frequently asked questions

What is a P11D and which benefits are reportable?: A P11D is the HMRC form an employer files annually (by 6 July) to report each employee's taxable Benefits in Kind. Common reportable benefits include company cars and fuel, private medical insurance, gym membership, employer-provided living accommodation, interest-free loans above £10,000, and other non-cash perks. Cash bonuses run through PAYE so do not appear on the P11D - they are taxed at source. Benefits run through payroll ("payrolled" benefits) also bypass the P11D, but the underlying tax cost is identical.
How is the company car BIK calculated in 2026/27?: Company car BIK = P11D list price x appropriate percentage. The appropriate % depends on CO2 emissions: fully electric cars are 4% in 2026/27 (rising 1pp per year to 9% in 2029/30); plug-in hybrids 4-16% banded by electric-only range; petrol and hybrids scale from 17% at 51-54 g/km up to a 37% cap. Diesel cars not meeting RDE2 add a 4 percentage-point supplement (still capped at 37%). All 2021+ diesels typically meet RDE2 so avoid the supplement.
What is the fuel benefit charge for 2026/27?: If your employer pays for private fuel in a company car, HMRC charges you tax on a notional fuel benefit. The 2026/27 charge is calculated as your car's appropriate % multiplied by £28,200 (the published Fuel Benefit Charge multiplier; HMRC updates this annually with CPI). At 30% appropriate %, that is £8,460 added to your taxable income - £3,384 a year for a 40% taxpayer. For most employees this works out worse than paying for fuel yourself, so private fuel benefits are rarely worthwhile unless your private mileage is very high. Electric cars are exempt - HMRC does not treat electricity as fuel for P11D purposes.
How is private medical insurance taxed?: The full annual premium your employer pays for your private medical or dental cover (and any covered dependants) is the cash equivalent reported on your P11D. It is added to your taxable income for Income Tax at your marginal rate. A £1,500/year policy costs a 40% taxpayer £600/year in tax. Your employer also pays Class 1A National Insurance at 15% on the £1,500 - a £225 employer-side cost.
Who pays National Insurance on Benefits in Kind?: BIKs do not attract employee National Insurance under the standard P11D route - only the employer pays Class 1A NI at 15% (2026/27 rate, aligned with the main Class 1 Secondary rate from April 2025). This is one reason BIKs and especially salary-sacrifice EVs are tax-efficient: a £1,000 salary increase costs the employer 15% NI AND triggers 8% (or 2%) employee NI; the same £1,000 of BIK costs the employer only the 15% Class 1A and the employee nothing in NI.
Should I take a company car or a cash allowance?: It depends on three things: the appropriate %, your marginal tax rate, and what you would do with the cash alternative. For electric cars (4% in 2026/27) the BIK route is usually overwhelmingly cheaper than a cash allowance - a £50,000 EV costs a 40% taxpayer £800/year in tax versus £20,000+ a year if they took the cash and bought the same car post-tax. For petrol/diesel above ~120 g/km, the cash allowance often wins. Salary sacrifice on low-emission cars (under 75 g/km) is also exempt from the "optional remuneration arrangement" anti-avoidance rule, preserving the BIK route.
What is the difference between payrolled benefits and P11D?: Both produce the same Income Tax outcome - the difference is timing and administration. Payrolled benefits are taxed in real time through PAYE each pay period (no end-of-year P11D needed, employer must register before the tax year starts). P11D-reported benefits are taxed via a tax-code adjustment after HMRC processes the form, usually meaning a lower tax code for the following year. From April 2026 most BIKs will become mandatorily payrolled (HMRC has confirmed this is the direction of travel), with only a few exceptions like employer-provided accommodation continuing on P11D.
What happens to BIK when income hits the £100k personal-allowance taper?: Between £100,000 and £125,140 of adjusted net income, Personal Allowance is withdrawn at £1 for every £2 above £100k - producing a 60% effective marginal rate. BIKs add to adjusted net income, so a company car BIK that pushes you from £95k into the taper zone is taxed at 60% on the slice above £100k, not the 40% you might expect. The calculator handles this automatically by running the salary engine with and without the BIK and using the actual Income Tax delta.