UK EV BiK Calculator: Company Car Tax from 3% to 9% (2025-2030)

A 40% taxpayer driving a £45,000 electric company car pays £540 in BiK tax this year. By 2029/30, that same car costs £1,620. The difference is a 3x increase that most fleet managers have not modelled.

HMRC has confirmed the zero-emission BiK trajectory through to 2029/30. The rates are locked in, the maths is straightforward, and the window to lock in low-rate leases is narrowing. This guide breaks down the formula, walks through worked examples at every tax band, and gives you the numbers you need to make a decision.

🔗 Want the full picture on how BiK fits into salary sacrifice? See our EV Salary Sacrifice Scheme UK 2026: Complete Fleet Guide.

How BiK tax works for electric vehicles

Benefit-in-Kind tax is the cost an employee pays for the "benefit" of having a company-provided car available for personal use. The calculation has three inputs:

Annual BiK tax = P11D value × BiK rate × personal tax rate

The P11D value is the car's list price including VAT, delivery charges and factory-fitted options, minus the first year of VED and the registration fee. This is not the same as the On The Road (OTR) price you see in a configurator. For a Tesla Model 3 Long Range, the P11D value is approximately £44,990 versus an OTR of around £46,490.

The BiK rate for zero-emission vehicles is set by HMRC and confirmed for five years. For ICE vehicles, the rate ranges from 19% to 37% depending on CO2 emissions.

The personal tax rate is the employee's marginal income tax rate: 20%, 40% or 45%.

Why P11D matters for your fleet: If your EV database or leasing quotes show OTR prices, you will overstate the BiK liability. Always ask for the P11D value, or subtract first-year VED (£10 for BEVs) and the £55 registration fee from the OTR.

The confirmed BiK trajectory: 2025 to 2030

HMRC has published zero-emission BiK rates through 2029/30. Here is what your fleet will face:

For context, a comparable diesel company car at 130 g/km CO2 attracts a 37% BiK rate. On the same £40,000 P11D, a 40% taxpayer would pay £5,920 per year. Even at the 2029/30 EV rate of 9%, the electric car saves that driver £4,480 annually in BiK tax alone.

Fleet move: If you are signing 4-year leases starting in 2025/26, your drivers will experience BiK rising from 3% to 7% over the term. Model this trajectory now so drivers are not surprised by a year-on-year increase in their payslip deduction.

Worked example: Tesla Model 3 Long Range

Let us put real numbers to a popular fleet choice.

Vehicle: Tesla Model 3 Long Range

P11D value: £44,990

Employee: 40% taxpayer earning £55,000

The employer pays Class 1A National Insurance at 15% on the BiK value each year. Over four years, that is £1,281 in employer NIC for a single vehicle. For a fleet of 50 Teslas, that becomes £64,050.

Compare this to a diesel alternative at 37% BiK: the employer NIC alone would be £9,988 per vehicle over four years (£499,400 for 50 vehicles). The EV saves the employer £8,707 per car in NIC costs.

Fleet move: When building your business case, do not forget employer NIC. It is the hidden cost that finance directors rarely model but that makes the strongest case for electrification.

🔗 For a full TCO comparison including fuel, maintenance and residual values, see our UK EV Fleet TCO Guide 2025-26.

What the calculator includes (and why it matters)

Most online BiK calculators show a single year and a single number. That is not enough for fleet planning. The EVDC BiK Calculator is built for fleet managers who need to model costs across an entire lease term.

What EVDC calculates:

• BiK tax by year at your chosen tax band (20%, 40% or 45%), using the confirmed HMRC trajectory from 2025/26 through 2029/30

• Employer Class 1A NIC at 15% on the BiK value each year, so you can see the total employer cost alongside the employee cost

• VED (Vehicle Excise Duty) including the first-year rate, standard rate from year 2, and the Expensive Car Supplement for vehicles with a list price above £50,000 (the new zero-emission threshold from April 2026)

• Multi-year totals across your chosen lease horizon, so you can compare a 3-year versus 4-year deal

  What makes it different from generic calculators:

  The tool is connected to EVDC's database of 101 electric vehicles with verified P11D values. Select a vehicle and the P11D is pre-filled. No guessing, no confusing OTR with P11D, no outdated pricing.

  It also shows the employer cost alongside the employee cost. Most calculators focus only on the driver's tax bill, but the employer NIC saving is often the single largest financial argument for switching to electric.

  🔗 Try the calculator now at /tools/bik-calculator.

Three scenarios fleet managers should model

Scenario 1: Affordable EV under £40,000

MG4 EV Long Range, P11D £31,990

A 20% taxpayer pays just £192 in BiK tax in 2025/26 (£16 per month). Even by 2029/30, the annual bill is only £576 (£48/month). The employer NIC over 4 years totals £912.

This vehicle also qualifies for the Electric Car Grant at £3,750 (Band 1, base variant under £37,000), further reducing the effective cost.

Scenario 2: Premium EV approaching the £50,000 threshold

BMW iX1 xDrive30, P11D £48,500

Watch the Expensive Car Supplement. From April 2026, zero-emission vehicles with a list price above £50,000 attract an additional £425/year in VED from year 2 onwards. The iX1 falls just below this threshold. But if your drivers are adding options that push the list price above £50,000, you will pay an extra £1,275 over a 4-year lease (£425 × 3 years, since year 1 is exempt).

Fleet move: Spec your vehicles carefully. A £500 options package could cost you £1,275 in Expensive Car Supplement if it tips the list price over £50,000.

Scenario 3: High-value fleet car

Tesla Model S, P11D £82,990

A 45% taxpayer pays £1,120 in BiK in 2025/26, rising to £3,361 by 2029/30. The equivalent ICE (say, a BMW 5 Series at 37% BiK) would cost £13,818 per year. The EV still saves over £10,000 annually, but the trajectory matters for retention. A driver who joined for "nearly free" company car tax needs to understand the cost will triple over five years.

Key pitfalls when calculating BiK

P11D is not OTR. P11D excludes first-year VED and registration fee. Using OTR will overstate the benefit.

BiK rates only go up. The 3% rate is the floor, not the norm. Any lease signed today will see rising BiK costs. Always model the full trajectory.

Employer NI is 15%, not 13.8%. From April 2025, employer NI Class 1 and Class 1A both moved to 15%. Some older calculators still use 13.8%.

The Expensive Car Supplement threshold changed. For zero-emission vehicles registered from April 2026, the threshold rises from £40,000 to £50,000. But this only applies to licence renewals from year 2. First-year VED uses the standard rate regardless.

Employee NI on salary sacrifice is not flat. If you are combining BiK with a salary sacrifice scheme, remember that employee NI is 8% on earnings up to £50,270 and 2% above that. A £55,000 earner sacrificing £6,000 saves a blended rate, not a flat 8%.

🔗 For the full salary sacrifice calculation including NI bands, see our Salary Sacrifice Guide.

Next steps for your fleet

The numbers are clear. Even at 9% by 2029/30, electric company cars remain dramatically cheaper in BiK tax than any ICE alternative. The question is not whether to switch, but how quickly you can lock in leases at today's rates.

• [ ] Model your fleet's BiK trajectory using the EVDC BiK Calculator at /tools/bik-calculator

• [ ] Compare against your current ICE fleet costs to quantify the savings for your board paper

• [ ] Check vehicle eligibility for the Electric Car Grant (£3,750 Band 1) in our Grants & Incentives Guide

• [ ] Run a full fleet audit with EVDC's Audit Express to get vehicle-by-vehicle recommendations

  🔗 For a deeper analysis covering charging costs, maintenance, residual values and route-to-zero planning, try the Fleet-Savings Calculator.

Sources

• HMRC BiK rates for company cars: gov.uk/guidance/rates-and-thresholds-for-employers-2025-to-2026

• Company car BiK bands confirmed to 2029/30: gov.uk/government/publications/company-car-benefit-in-kind-rates

• VED rates and Expensive Car Supplement: gov.uk/vehicle-tax-rate-tables

• Employer NIC Class 1A rates: gov.uk/guidance/rates-and-thresholds-for-employers-2025-to-2026

• Electric Car Grant eligibility: gov.uk/plug-in-car-van-grants