Plug in your vehicle, salary, and tax band. Get your monthly company car tax — the benefit-in-kind (BIK) charge — in plain pounds, side by side with the same calc for an EV and a petrol equivalent. No email, no sign-up, no funnel. The figures come straight from HMRC’s published rates.
Which car?
Type to filter. 49 vehicles in the launch dataset.
How this calculator works
Three things determine your benefit-in-kind tax on a company car: the car’s P11D value, the BIK percentage for the vehicle’s CO2 emissions (and electric range, for PHEVs), and your marginal income tax rate. Multiply the three together and you have your annual BIK tax bill. Divide by 12 for the monthly figure.
The formula:
Annual BIK tax = P11D value × BIK percentage × your income tax rate
P11D value is the car’s list price including delivery charges and any factory-fitted options, but excluding first-year VED and the £55 first registration fee. It’s set when the car is registered and doesn’t change.
BIK percentages are set by HMRC and published years ahead. For 2026/27 they range from 4% (pure EV) to 37% (high-emission petrol). For plug-in hybrids in the 1–50g/km CO2 band, the percentage depends on electric range as well as emissions, with five sub-bands from 4% (130+ miles, no model currently achieves this) down to 16% (under 30 miles).
Your income tax rate is your marginal rate: 20% if your salary plus the BIK value lands within the basic-rate band, 40% if higher rate, 45% if additional rate.
A 4% EV at £45,000 P11D, taxed at 40%: £45,000 × 4% × 40% = £720 per year, or £60 per month. A 31% petrol at £30,000 P11D, same tax band: £30,000 × 31% × 40% = £3,720 per year, or £310 per month. The arithmetic isn’t complicated. The choice of car is.
One quirk to flag: for salary sacrifice on cars over 75g/km CO2, the Optional Remuneration Arrangements (OpRA) rule applies. You pay tax on the higher of the cash given up or the BIK value, whichever is greater. This catches most petrol and diesel salary sacrifice arrangements. EVs and most modern PHEVs are below 75g/km and exempt from OpRA, which is the structural reason EV salary sacrifice schemes work.
Assumptions
This calculator uses HMRC’s published BIK percentages for the relevant tax year, sourced from gov.uk and the Autumn 2024 Budget company car tax tables. Vehicle data is synthesised from manufacturer specifications and HMRC’s own vehicle database.
A few specific assumptions worth flagging:
- Income tax bands: we use rest-of-UK rates (England, Wales, Northern Ireland). Scottish residents pay slightly different rates above £43,663. A Scottish-rates toggle will be added if reader demand justifies it.
- Personal allowance taper: factored in between £100,000 and £125,140 of total income (the effective 60% marginal rate zone).
- Class 1A NIC: the calculator shows the employee tax burden only. Your employer pays 15% Class 1A NIC on the same BIK value (rose from 13.8% in April 2025); this doesn’t affect your personal tax but is relevant for total cost-of-ownership conversations.
- Diesel surcharge: applied automatically (+4%, capped at 37%) where a diesel vehicle is selected and isn’t RDE2-compliant. Most diesels registered from January 2021 onwards are RDE2-compliant.
- What we don’t model: employer NIC reimbursement, the fuel benefit charge (£28,200 × BIK% in 2026/27 for company-paid private fuel), capital contributions you’ve made towards the car, or part-year availability. If any of these apply to your situation, your actual figure will differ.
What is BIK and how does it work?
Benefit-in-kind tax is what you pay when your employer gives you something other than salary. For company cars made available for private use (including weekday-evening shopping trips, not just weekend leisure), HMRC treats the car as a taxable benefit and applies an annual charge based on the car’s P11D value and CO2 emissions.
The system is deliberately weighted toward low-emission vehicles. A pure-EV company car costs roughly one-eighth the BIK of an equivalent petrol car in 2026/27. The gap is the whole reason salary sacrifice schemes for EVs have grown so quickly. Even at the 2029/30 cap of 9%, an EV will still beat a typical petrol car by three to four times.
The same rules apply whether your company car comes through a traditional company car scheme or through salary sacrifice. The tax treatment is identical for cars under 75g/km CO2. Above 75g/km, the Optional Remuneration Arrangements rule (covered below) changes the calculation under salary sacrifice.
BIK rates 2024/25 through 2029/30
The rates below are HMRC’s published company car tax bands, set out in the Autumn 2024 Budget. They’re confirmed through 2029/30, which makes a salary sacrifice scheme signed today predictable until the end of the decade.
Pure electric vehicles (0g/km CO2)
| Tax year | BIK % |
|---|---|
| 2024/25 | 2% |
| 2025/26 | 3% |
| 2026/27 | 4% |
| 2027/28 | 5% |
| 2028/29 | 7% |
| 2029/30 | 9% |
Plug-in hybrids (1–50g/km CO2), by electric range
| Electric range | 2024/25 | 2025/26 | 2026/27 | 2027/28 | 2028/29 | 2029/30 |
|---|---|---|---|---|---|---|
| 130+ miles | 2% | 3% | 4% | 5% | 18% | 19% |
| 70–129 miles | 5% | 6% | 7% | 8% | 18% | 19% |
| 40–69 miles | 8% | 9% | 10% | 11% | 18% | 19% |
| 30–39 miles | 12% | 13% | 14% | 15% | 18% | 19% |
| Under 30 miles | 14% | 15% | 16% | 17% | 18% | 19% |
Petrol, diesel and hybrid (51g/km CO2 and above)
Rates for vehicles emitting 75g/km or more are frozen at 2025/26 levels through 2027/28, then rise 1% per year in 2028/29 and 2029/30. The cap rises from 37% to 38% in 2028/29 and 39% in 2029/30. A condensed view:
| CO2 emissions | 2026/27 | 2027/28 | 2028/29 | 2029/30 |
|---|---|---|---|---|
| 75–79g/km | 21% | 21% | 22% | 23% |
| 100–104g/km | 26% | 26% | 27% | 28% |
| 125–129g/km | 31% | 31% | 32% | 33% |
| 150–154g/km | 36% | 36% | 37% | 38% |
| 160g/km+ | 37% | 37% | 38% | 39% |
The full table runs in 1% increments per 5g/km of CO2. The calculator handles the exact figure for any emissions reading; the table above is for reference.
The PHEV story bears closer attention. In 2026/27 a PHEV with 70+ miles of electric range attracts a 7% BIK rate. In 2028/29 the same car jumps to 18%. The government is removing electric range as a tax variable from April 2028, treating all 1–50g/km hybrids identically regardless of how far they can travel on battery. If you’re signing a four-year PHEV salary sacrifice deal in 2026, the third and fourth years will cost roughly 2.5 times the first two in BIK.
The diesel surcharge
Diesel company cars carry a 4% supplement on top of the standard CO2-based BIK percentage, capped at 37% total. The surcharge applies to diesels that don’t meet the Real Driving Emissions Step 2 (RDE2) standard. Most diesels registered from January 2021 onwards are RDE2-compliant and exempt; older diesels and some specific models still carry the surcharge.
Two exemptions worth knowing. Diesel plug-in hybrids are classed as alternative fuel vehicles and the 4% supplement doesn’t apply regardless of RDE2 status. Petrol cars never carry the surcharge. If you’re unsure whether your specific diesel is RDE2-compliant, check the certificate of conformity supplied with the vehicle, or use the calculator’s diesel toggle to compare both treatments.
The OpRA rule: salary sacrifice on cars over 75g/km
Optional Remuneration Arrangements rules were introduced in April 2017 to close a loophole where salary sacrifice schemes were undercutting normal BIK valuations. Under OpRA, for most benefits given via salary sacrifice, you pay tax on the higher of the cash given up or the cash-equivalent benefit value.
Cars with CO2 emissions of 75g/km or less are exempt. This single carve-out is the structural reason EV salary sacrifice schemes work. For an EV (0g/km) or a modern PHEV with realistic emissions (most are 20–35g/km), OpRA doesn’t apply and the BIK is calculated normally on the car’s cash-equivalent value.
For petrol or diesel cars over 75g/km under salary sacrifice, OpRA bites. If you sacrifice £500 per month gross (£6,000 per year) for a car whose BIK cash-equivalent value is £4,500 per year, you pay tax on £6,000, the higher figure. This usually wipes out the tax efficiency of putting a non-low-emission car through salary sacrifice. The calculator applies the OpRA rule automatically where the fuel type and emissions trigger it.
Three worked examples
Tesla Model Y Long Range RWD (P11D £44,990): pure EV
40% taxpayer in 2026/27: £44,990 × 4% × 40% = £720 per year, £60 per month in BIK tax.
20% taxpayer: £44,990 × 4% × 20% = £360 per year, £30 per month.
In 2029/30 at the 9% cap, the 40% taxpayer pays £1,620 per year, still a third of what a typical petrol equivalent would cost.
BMW 330e M Sport (P11D £48,000, 25g/km CO2, 63-mile electric range): PHEV
40% taxpayer in 2026/27, in the 40–69 mile electric range band at 10% BIK: £48,000 × 10% × 40% = £1,920 per year, £160 per month.
From 2028/29 the same car jumps to a flat 18% BIK regardless of range: £48,000 × 18% × 40% = £3,456 per year, £288 per month. Worth knowing if you’re signing a four-year contract today.
Volkswagen Golf 1.5 TSI Style (P11D £29,560, 126g/km CO2): petrol
40% taxpayer in 2026/27, 125–129g/km band at 31%: £29,560 × 31% × 40% = £3,665 per year, £305 per month.
Note the inversion: the Golf costs less than half what the BMW costs new, but generates over 90% more BIK tax. CO2 emissions and the BIK percentage drive the tax burden far more than the P11D value does. This is the entire economic logic of the EV salary sacrifice market.
Sources: See sources cited below.
Corrections: if we got something wrong, tell us and we'll fix it in public, dated and signed. Last updated 27 May 2026.
Sources
- HMRC EIM23900: Company cars introduction — accessed 27 May 2026
- HMRC EIM24010: Cars, calculating the cash equivalent — accessed 27 May 2026
- gov.uk: Tax on company cars — accessed 27 May 2026
- Autumn Budget 2024: Company car tax rates 2028/29 and 2029/30 — accessed 27 May 2026
- HMRC EIM44030: Optional Remuneration Arrangements (cars) — accessed 27 May 2026
- House of Commons Library: Direct taxes, rates and allowances 2026/27 — accessed 27 May 2026