Company Car Benefit-in-Kind Tax Calculator
Estimate the employee tax cost of a company car from its P11D value, CO2 emissions, electric range and your marginal tax rate. The calculator also shows private fuel benefit, diesel supplement warnings, employer Class 1A National Insurance and a quick comparison with an electric-car route.
Estimate company car BiK tax
Use the list/P11D value before discounts. If the car is a plug-in hybrid, enter the official electric range from the certificate or employer data.
Choose the rate that applies to the extra benefit. Use the take-home calculator if the benefit crosses tax bands.
Leave at zero if your employer's P11D value already includes them.
Choose non-Euro 6d if the diesel car does not meet the supplement exemption.
Only used where CO2 is 1 to 50g/km.
HMRC caps qualifying capital contributions at GBP 5,000.
A simple month-based estimate. HMRC works by days.
Payments specifically required for private use, not fuel or insurance.
Fully electric
4%
The 2026/27 appropriate percentage for a zero-emission company car.
PHEV band
4% to 16%
For 1 to 50g/km cars in 2026/27, depending on electric range.
Fuel multiplier
GBP 29,200
The official 2026/27 car fuel benefit multiplier.
The comparison that matters
Company car tax is not based on your monthly lease cost. It starts with the car's list price and then applies the official percentage for the car's emissions. That is why a higher-list-price electric car can sometimes cost less in tax than a cheaper petrol or diesel car with a much higher percentage.
The calculator is built as a comparison-first journey because the practical question is rarely just "what is the tax?" It is usually "is this car still worth taking?", "what if I choose the EV?", or "is free fuel a trap?" The result therefore shows the annual car benefit, monthly employee tax, private fuel cost and a like-for-like electric-car comparison using the same P11D value.
If your employer offers a cash allowance instead of a company car, compare the estimated BiK tax with the extra salary using the Take-Home Pay Calculator. The company car answer can still be better if insurance, maintenance, tyres, breakdown cover and risk sit with the employer, but the tax result is the clean starting point.
| 2026/27 car type | Typical BiK percentage |
|---|---|
| Fully electric, 0g/km | 4% |
| PHEV, 1 to 50g/km, 40-69 mile range | 10% |
| Petrol/hybrid, 100 to 104g/km | 26% |
| High-emission or diesel after cap | Up to 37% |
How this company car BiK calculator works
Inputs used
- Tax year, because the official appropriate percentage and fuel benefit multiplier can change.
- P11D/list price and taxable accessories, before deducting qualifying employee capital contributions.
- CO2 emissions, fuel type, diesel Euro 6d/RDE2 status and electric range for plug-in hybrids.
- Availability period, employee private-use payments and whether private fuel is provided.
- The employee marginal Income Tax rate, plus optional employer Class 1A National Insurance estimate.
Calculation method
- Build the adjusted car value from list price plus accessories, then deduct employee capital contribution capped at GBP 5,000.
- Choose the appropriate percentage from the official CO2 and electric-range table for the selected tax year.
- Add the 4 percentage point diesel supplement for non-Euro 6d/RDE2 diesel cars, capped at 37%.
- Multiply adjusted value by the percentage, reduce for the months available, then deduct qualifying private-use payments.
- If private fuel is provided and not made good, multiply the fuel benefit multiplier by the same appropriate percentage and availability fraction where the multiplier has been published.
- Apply the selected marginal Income Tax rate to the car and fuel benefit, and show employer Class 1A NI at 15% for 2025/26 and 2026/27. For 2027/28, Class 1A is shown as a current-rate assumption until the employer NI rate is published for that year.
Assumptions
- The availability reduction is estimated by months for usability. HMRC calculations normally use days and only treat a car as unavailable during qualifying periods.
- The calculator assumes the P11D/list price is already the correct value for the car. Discounts, lease rentals and second-hand purchase prices are not substituted for list price.
- For plug-in hybrids registered on or after 1 January 2025, GOV.UK has a special CO2 rule where some certificates show 51g/km or more but the car has at least 1 mile electric range. This calculator uses the CO2 figure you enter, so check the official guidance and your employer data.
- Use the Take-Home Pay Calculator if the benefit pushes you across tax bands or interacts with student loans, pension tapering or the Personal Allowance taper.
- The 2027/28 company car percentages are officially published, but the 2027/28 car fuel benefit multiplier had not been published at the last verification date, so this calculator uses the latest published multiplier as a provisional assumption if private fuel is selected for 2027/28.
What this does not cover
- It does not calculate van benefit. Pick-ups, double-cab vehicles and Ford Ranger-style cases can depend on classification; see the Ford Ranger Road Tax Calculator and official vehicle classification guidance.
- It does not calculate Vehicle Excise Duty, showroom tax, expensive-car supplement or registration charges. Use the Road Tax Calculator or Car Registration Tax Calculator for those.
- It does not handle salary sacrifice optional remuneration arrangements, classic cars, shared cars, multiple cars, disabled-driver modifications, pool cars, mileage reimbursement or exact payroll coding. HMRC 480 guidance and employer payroll data should be used for those cases.
Worked example: PHEV versus EV
Say a higher-rate taxpayer chooses a GBP 42,000 plug-in hybrid in 2026/27. It has CO2 emissions of 48g/km and an official electric range of 40 miles. The 2026/27 table puts that in the 10% band, so the annual car benefit is GBP 4,200 before any availability or private-use reductions.
At 40% tax, the employee tax is GBP 1,680 a year, or GBP 140 a month. If the employer also pays for private fuel and the employee does not make good all private fuel, the fuel benefit is GBP 29,200 multiplied by 10%, adding GBP 2,920 of taxable benefit and GBP 1,168 of tax for that higher-rate employee.
A GBP 42,000 fully electric car in 2026/27 uses a 4% percentage. That is GBP 1,680 of car benefit and GBP 672 of tax at 40%, about GBP 56 a month. The list price is the same, but the emissions percentage changes the tax result dramatically.
Private fuel decision checklist
Private fuel benefit is one of the easiest company-car costs to underestimate. It is not based on the fuel you actually use. It uses the fixed multiplier and the car's appropriate percentage, so a high-percentage car can create a large taxable fuel benefit even for modest private mileage.
- Check whether the employer pays only business fuel or also private fuel.
- Ask whether you can reimburse all private fuel and remove the benefit.
- Compare the tax cost with your realistic private mileage and fuel price.
- Remember commuting is normally private travel for company car purposes.
If the calculator shows private fuel tax that is higher than the value of your private fuel, the arrangement may be poor value. That does not mean it is always wrong, but it is a signal to ask payroll exactly how the fuel card or reimbursement policy is reported.
Common company car tax mistakes
Using lease cost instead of P11D value
The tax starts from list price when new. A discounted lease or a cheap used purchase does not usually reduce the list-price basis.
Forgetting the diesel supplement
Non-Euro 6d/RDE2 diesel cars get a 4 percentage point uplift, subject to the overall 37% cap.
Guessing the PHEV range
The electric range must be the official zero-emission mileage figure, not the range you normally achieve on a cold motorway morning.
Treating employer NI as employee tax
Class 1A NI is an employer cost on benefits. It may affect fleet policy, but it is not deducted from your payslip like Income Tax.
Company car BiK FAQs
How is company car tax calculated?
Why are EVs cheaper for Benefit-in-Kind?
What is P11D value?
How is private fuel taxed?
Does this cover salary sacrifice company cars?
Official sources
Last verified: May 10 2026. Calculations are estimates based on the published rules and assumptions shown on this page.
- GOV.UK tax on company cars - private use, commuting, low-emission reductions, fuel benefit and plug-in hybrid electric range rules
- HMRC 480 Appendix 2 - appropriate percentages - official 2025/26 and 2026/27 CO2 and electric-range percentage tables
- GOV.UK future company car rates - published company car percentage tables for 2025/26, 2026/27 and 2027/28
- HMRC 480 Chapter 12 - company car benefit method - P11D/list price, accessories, capital contribution, availability, private-use payments and diesel supplement rules
- GOV.UK travel, mileage and fuel allowances - car fuel benefit multipliers for 2025/26 and 2026/27
- HMRC Employment Income Manual EIM25580 - car fuel benefit multiplier, including the 2026/27 amount
- GOV.UK Income Tax rates and allowances - current UK basic, higher and additional Income Tax rates
- Scottish Government Income Tax rates - Scottish starter, basic, intermediate, higher, advanced and top rates for 2026/27
- GOV.UK National Insurance rates - Class 1A rate on expenses and benefits for 2025/26 and 2026/27