The Allowance Illusion: What Your Company Car Money Is Actually Worth After HMRC Takes Its Cut

Ask any HR department about company cars and you'll likely hear the same line: we offer a cash allowance instead, giving employees flexibility and choice. It sounds empowering. It is also, in the majority of cases, the worse financial outcome for the employee — and the arithmetic behind that claim deserves to be spelled out properly.

The Core Problem with Cash

A car allowance is simply salary by another name. That £6,000 allowance is added to your taxable income, which means it's subject to income tax at your marginal rate and both employer and employee National Insurance contributions. What lands in your bank account is materially less than the headline figure.

Then comes the second problem: the money has to buy, run and insure a car entirely on your own terms — with no fleet discount, no maintenance plan and no residual value risk taken by anyone but you.

Running the Numbers: Three Typical Drivers

Let's compare a £6,000 cash allowance against a like-for-like benefit-in-kind (BIK) company car. For fairness, we'll use a popular mid-size electric saloon with a P11D value of £40,000 and a CO2 figure that places it in the 2% BIK band — the current rate for the cleanest EVs.

Case one: a basic-rate taxpayer on £30,000. The £6,000 allowance attracts 20% income tax plus 8% employee NI, leaving roughly £4,320 in the pocket. A brand-new £30,000 petrol hatchback on a personal lease might cost £280 a month — £3,360 a year — leaving about £960 spare. On paper, close. But add insurance for a young driver, servicing, tyres and depreciation risk on any purchase rather than lease, and the margin evaporates. The equivalent EV company car generates a BIK charge of just £40,000 × 2% = £800 a year, taxed at 20% — £160. The company car wins comfortably.

Case two: a higher-rate taxpayer on £60,000. The allowance now loses 40% to income tax plus 2% NI, leaving about £3,480. That no longer covers a credible personal lease on anything comparable to what a fleet buyer can command. Meanwhile, the EV company car costs £800 × 40% = £320 a year in tax. The gap is now enormous — several thousand pounds a year.

Case three: an additional-rate director on £130,000. The allowance retains barely £3,180 after 45% tax. The company car tax remains £360. Unless the driver was planning to buy outright and hold the car for a decade, the allowance is close to financial malpractice as an employee benefit.

Where the Allowance Can Still Work

Intellectual honesty requires balance. A cash allowance suits a narrow but real group: drivers who already own a reliable car outright, those who genuinely want to buy an asset and run it long-term, and very low-mileage employees for whom a car is a marginal cost anyway. Anyone claiming mileage at HMRC's Approved Mileage Allowance Payments (45p per mile for the first 10,000 miles) can also extract value from a personally-owned vehicle.

But these are exceptions wearing the costume of a general policy.

The Electric Wildcard

The reason this debate has reignited is the EV BIK regime. Company car tax on the cleanest electric vehicles sits at 2% — frozen at that level through 2027-28 before rising gently — compared with rates of 20-37% for comparable petrol and diesel models. A higher-rate taxpayer running a £60,000 petrol saloon in the 37% band would face over £8,000 a year in company car tax. The same money in an EV costs a few hundred pounds.

This has inverted the conventional wisdom of the 2010s, when salary sacrifice and company schemes fell out of favour. Fleet providers and leasing brokers report record demand for EV salary sacrifice schemes precisely because the tax system now makes the company route — with insurance, maintenance, breakdown cover and early-termination protection bundled in — almost impossible to beat for anyone paying 40p-plus in the pound.

What HR Won't Volunteer

Three points rarely appear in the offer letter:

1. Allowances are pensionable in some companies and not others. If yours isn't, you're also losing retirement contributions on that money.
2. Allowance values are frozen while salaries rise, meaning the real value of your car budget erodes every year against vehicle price inflation.
3. Employers save National Insurance too when staff take a company car via salary sacrifice rather than taxable cash — some pass a share of this on; many don't. It's a reasonable question to ask.

The Verdict

For the typical employee driving a meaningful annual mileage, the cash allowance is a tax-inefficient compromise that transfers risk without transferring reward. The company car — specifically, the electric company car — has reclaimed its place as the financially rational choice for the majority of UK drivers in the 40% and 45% brackets, and increasingly for basic-rate taxpayers too.

The next time a job offer dangles a generous allowance, don't ask what it's worth. Ask what's left of it after HMRC has taken its share — then price the company car alternative properly. The answer frequently surprises people.