Getting a company car is nice.
Really nice.
It’s a brand new machine. Fully maintained. The business pays for the fuel (sometimes). You get to drive it on the weekend. For the UK’s 840 million or so drivers lucky enough to qualify, it feels like the ultimate perk.
There’s a catch though.
His Majesty’s Revenue and Customs calls this a Benefit-in-Kind.
BiK for short. It means your car is a perk added to your salary, and perks get taxed. Just like cash in your paycheck, this “car salary” has a price tag. You will pay tax on it.
How much you pay depends on two things. The car you pick. And how much you already earn. It sounds complicated because HMRC loves jargon, but underneath it all? The math is actually pretty straightforward. You can keep the costs down. You just need to know which lever to pull.
The messy math
It isn’t linear.
One car costs a lot. Another one, seemingly identical, might barely touch your bill. HMRC slaps a taxable value on every company vehicle. They figure this out using a percentage of the list price, heavily weighted by how much carbon comes out of the tailpipe. For plug-in hybrids, the electric range matters too. More electric miles mean a lower tax bill.
That list price—known as P11d —is sticky. It includes VAT. Delivery fees. Any fancy optional extras you ticked off. But it doesn’t include the registration fee or the road tax. Crucially, this price is fixed for the life of the car. Market discounts? Irrelevant. Buying a used car to save tax? Doesn’t help the P11d calculation. The number is set. It doesn’t budge.
So here’s the bill. You take that taxable value and apply your income tax rate to it. If you’re a 20% taxpayer, you pay 20% of that car’s taxable value. A basic 40%? You pay more. A high earner on 45%? Watch your wallet. Scotland has its own rates, which is another headache, but the logic holds. The money comes out of your monthly wages. Bit by bit.
Simple rule. Cheaper car. Lower emissions. Lower tax.
Finding your band
You need data. Specifically, tailpipe CO2 emissions. If you’re eyeing a plug-in hybrid, you need the official electric range too. Don’t guess. Guessing gets expensive.
Most manufacturers have online tools that spit these numbers out instantly. Leasing companies do too. If they don’t? Ask your fleet manager. They live in these spreadsheets. It’s what they do.
Is it fair that the electric range changes everything? Probably.
But that’s the game. You pick the car, you accept the tax bracket.
“The cheaper the vehicle and the less CO 2 it emits, the lower the tax bill.”
Sound logical. Until you try to find a car that fits.
