Car fuel benefit calculator, 2026/27

How this is calculated

The car fuel benefit is a flat notional figure, not your actual fuel spend. HMRC multiplies the fixed fuel benefit charge multiplier of £29,200 for 2026/27 by the same CO2-based appropriate percentage used for your car benefit, which ranges from 4.0% for zero-emission cars up to a cap of 37.0% for the highest-emission diesel and petrol cars.

That notional benefit is then taxed at your marginal rate of income tax through PAYE, typically via a coding notice adjustment or on your P11D and self assessment return. Your employer separately pays Class 1A National Insurance at 15% on the same figure, which is a real cash cost to the company even though you never see it.

Because the multiplier is fixed regardless of how much fuel you actually use, low-mileage private drivers are usually better off repaying the company for private fuel at HMRC's advisory fuel rates and opting out of the benefit altogether.

Deciding whether to keep the fuel benefit

The fuel benefit only makes financial sense if your genuine private fuel cost exceeds the tax and NIC cost of the benefit. For most higher-rate taxpayers with average mileage, the maths tips against it once private mileage drops below roughly 10,000 to 12,000 miles a year, though this varies by car and fuel price.

Directors with high private mileage in an efficient car, or who simply want the administrative simplicity of not tracking business versus private fuel, may still find it worthwhile despite the tax charge.

Alternatives worth considering

Repaying your employer for all private fuel at HMRC's published advisory fuel rates removes the benefit entirely, provided you repay before 6 July after the tax year ends. Many directors find this cheaper overall.

Switching to an electric or plug-in hybrid company car removes most of the fuel benefit question, since there is no equivalent taxable benefit for electricity provided at a workplace charging point.

Can I avoid the fuel benefit charge part way through the year?

Yes. If you stop having private fuel paid for by the company and repay all private fuel costs, the charge can be withdrawn from the date private fuel provision stopped, though HMRC applies this strictly.

Does the fuel benefit apply to electric cars?

No separate fuel benefit charge applies to electricity provided for an electric company car, because electricity is not treated as 'fuel' for these purposes. Charging costs reimbursed by the employer are generally tax-free.

Is it cheaper to just claim mileage instead?

Often yes for lower private mileage drivers. Repaying the company at advisory fuel rates for private journeys avoids the benefit charge entirely and usually costs less than the resulting tax and Class 1A NIC.

Does the multiplier change every year?

Yes, the fuel benefit multiplier is uprated annually by HMRC, usually each April, so a calculation from last year's rates will not match this year's exactly.