Company Car vs Cash Allowance in the UK: Hidden Tax Implications and Cost Pitfalls for 2026

Summary

Choosing between a company car and a cash allowance in 2026 is no longer a straightforward swap. Benefit-in-Kind rates for electric vehicles are creeping up, EVs now pay Vehicle Excise Duty, and cash allowances quietly transfer a stack of risks and running costs onto you. This guide walks through:

• the real numbers on each option
• the hidden traps
• how business mileage can swing the result
• how to work out which option actually leaves you better off

Use our Company Car vs Cash Allowance Calculator UK · BiK 25/26 to crunch your own figures.

Why This Decision Matters More in 2026

You might have just been offered a new role, or it might be contract review time. Either way, you've probably been handed a familiar question: do you want the company car, or the cash equivalent paid into your salary?

On the surface, it feels like a personal preference. In reality, the gap between the right and wrong choice can quietly cost you between £1,200 and £3,500 a year. The exact figure depends on your tax band, your mileage and the vehicle on the table.

The 2025/26 tax year was a turning point, and 2026/27 continues the squeeze:

• EV company car tax is rising. Electric vehicles were almost tax-free for years. They are now climbing the Benefit-in-Kind ladder by one percentage point a year until 2027/28, then by two points a year after that.
• EVs now pay road tax. Their Vehicle Excise Duty exemption ended in April 2025.
• Pay-per-mile road tax is coming. A charge on electric and plug-in hybrid cars has been announced from April 2028.
• Insurance is still expensive. Premiums have eased from their 2024 peak but remain well above pre-2023 levels.
• Mileage rates haven't moved. HMRC's Approved Mileage Allowance Payment rates, unchanged since 2011, still sit at 45p per mile for the first 10,000 business miles. That's despite running a private car costing considerably more than it did then.

All of that means the rules of thumb your colleagues swear by are probably out of date. There's also time pressure. In most schemes, delaying your decision locks you into the wrong choice for at least 12 months.

Before you sign anything, plug your numbers into our Company Car vs Cash Allowance Calculator UK · BiK 25/26 and read on. The headline figure on your offer letter rarely tells the full story.

How Company Car Tax Works in the UK

A company car is what HMRC calls a Benefit-in-Kind. You're not paid cash for it, but because it has personal value, the taxman wants a slice. Your tax bill depends on three things:

• The P11D value: the car's list price.
• The BiK percentage: a band set by the car's CO2 emissions and fuel type.
• Your marginal income tax rate.

The maths is simpler than people fear:

1. Multiply the P11D value by the BiK percentage. That gives you the taxable benefit.
2. Pay your income tax rate on that figure.

So a £40,000 car with a 10% BiK rate creates a £4,000 taxable benefit. That costs a 40% taxpayer £1,600 a year.

The 2026 BiK landscape

BiK percentages are set years in advance to give drivers and fleets some certainty. Pure electric vehicles sat at 2% from 2022/23 to 2024/25. They have now started to rise:

Petrol and diesel cars sit considerably higher, often between 25% and 37% depending on emissions.

EVs remain the most tax-efficient company car by a wide margin, but the gap is narrowing. A £50,000 EV will cost you more in tax each year you keep it, and the rises speed up from 2028.

What about fuel and charging?

If your employer also pays for your private fuel, that triggers a separate Car Fuel Benefit charge. This is almost always poor value unless you do enormous private mileage.

For EVs, the position is different:

• Workplace charging provided by your employer is currently free of BiK.
• Business mileage in a company EV is reimbursed using HMRC's Advisory Electricity Rate. This is updated quarterly and, since September 2025, has separate rates for home charging and public charging.

Many drivers get caught out by assuming all electricity reimbursement is tax-free. It isn't. If your employer reimburses you above the advisory rate for business journeys in a company car, the excess is taxable. Keep clean mileage records and check the current advisory rate each quarter.

The Cash Allowance: Simpler Looking, Trickier in Practice

A cash allowance sounds wonderfully straightforward. Your employer pays you, say, £6,000 a year extra in salary, and you go off and sort your own car. No BiK, no P11D, no fuss. Except the simplicity is mostly an illusion.

That £6,000 is treated as normal employment income. It is taxed at your marginal rate and pulled into National Insurance. A 40% taxpayer with a £6,000 allowance keeps roughly £3,480 after tax and employee NI.

Out of that £3,480, you must fund:

• lease or finance payments
• insurance
• road tax
• servicing and tyres
• depreciation

Suddenly £3,480 doesn't go very far.

Hidden cost number one: insurance

Personal car insurance with business use is a different beast to standard social, domestic and pleasure cover. Premiums have come down from their 2024 peak but remain well above pre-2023 levels, and adding business mileage typically pushes them up further.

Many drivers also discover that their cheap comparison-site quote excludes business use entirely. That leaves them uninsured the moment they drive to a client meeting.

Hidden cost number two: depreciation

This is the silent killer of cash allowance maths. A new £35,000 car can lose £8,000 to £12,000 of value in its first year.

• If you lease, the depreciation is smoothed into your monthly payments.
• If you buy outright or on finance, you absorb it directly.

People often compare the monthly lease cost to the after-tax allowance and forget one thing: a company car driver bears no depreciation risk whatsoever.

Hidden cost number three: business mileage tax relief

If you use your own car for business, your employer typically reimburses you per mile. HMRC's Approved Mileage Allowance Payment (AMAP) rates are:

• 45p per mile for the first 10,000 business miles
• 25p per mile after that

If your employer pays less than these rates, you can claim tax relief on the difference. You do this through your Self Assessment or by writing to HMRC.

Many employees never claim this relief and leave real money on the table. If this kind of detail catches you out, our guide on UK tax optimisers versus traditional calculators walks through how to spot deductions most people miss.

A Worked Example: The 2026 Comparison

Let's run through a realistic 2026 scenario.

Meet Priya, a marketing manager from Reading earning £72,000, which puts her firmly in the 40% tax band. She's been offered either a £45,000 electric company car or a £7,000 annual cash allowance. She drives 12,000 business miles and 8,000 personal miles each year.

1. Company car route. With a BiK rate of 4% for 2026/27, the taxable benefit is £1,800. At 40% tax, that costs Priya £720 a year.

• Her employer covers servicing, insurance, road tax, breakdown cover and depreciation.
• Business mileage is reimbursed at the Advisory Electricity Rate, which roughly covers her charging for work trips.
• She pays to charge her 8,000 personal miles at home, around £240.
• Total cost: about £960 a year.

2. Cash allowance route. Her £7,000 allowance becomes roughly £4,060 after 40% tax and 2% NI. From that, she funds:

• a personal lease at around £400 a month (£4,800)
• comprehensive insurance with business cover (£900)
• servicing and tyres (£400)
• home charging for all 20,000 miles (around £600)

Total running cost: around £6,700. On the allowance alone, she's £2,640 short.

3. The mileage offset. Her employer pays 25p per business mile for own-car use.

• On 12,000 miles, that's £3,000. It's tax-free because it's below HMRC's limits.
• HMRC's AMAP figure for 12,000 miles is £5,000 (10,000 miles at 45p plus 2,000 miles at 25p).
• She can claim tax relief on the £2,000 shortfall, recovering £800 at 40%.

4. Net result. £4,060 + £3,000 + £800 − £6,700 leaves Priya around £1,160 ahead. Against the company car's £960 cost, the cash route comes out roughly £2,100 better on these figures. That lead is fragile, though:

• A lease genuinely priced for 20,000 miles a year can easily cost £550 or more a month, which wipes out most of the gap.
• Buying rather than leasing adds thousands in depreciation risk.

5. The flip points. Small changes reverse the answer:

• Strip out the business mileage. Say all 20,000 of her miles were personal. The cash route then leaves her around £2,640 short, against roughly £1,320 for the company car (£720 tax plus £600 of charging). The company car wins by about £1,300.
• Change the car. Swap to a high-emission petrol model with a 35% BiK band, and the company car costs £6,300 a year in tax. The cash allowance then wins comfortably.

Grey Fleet: The Risk Employers Quietly Pass to You

When you take a cash allowance and drive your own car for business, you become part of what's known as the grey fleet. Employers are increasingly aware that this carries legal and duty-of-care obligations, but many push the practical burden onto employees.

You're typically required to prove that:

• your car is roadworthy and has a valid MOT
• business-use insurance is in place
• you hold a clean licence

Some employers now run annual checks on this documentation. If you fail to keep it up to date and have an accident on a business journey, you could face personal liability claims.

What employers should provide, but often don't

A decent grey fleet policy should cover several practical bases:

• A clear written policy explaining your obligations.
• Annual licence and insurance checks at the company's expense.
• Reimbursement at, or close to, HMRC's full Approved Mileage Allowance rates.
• Guidance on suitable vehicle age and safety standards.
• Cover or contribution towards business-use insurance loading.

Salary Sacrifice: The Often-Overlooked Middle Ground

A third option has grown rapidly in popularity: the salary sacrifice car scheme. You give up part of your gross salary in exchange for an employer-provided car, usually electric. Because the sacrifice happens before tax and NI, you effectively run the car with pre-tax money.

For EVs specifically, salary sacrifice can be remarkably efficient. You still pay BiK, but the income tax and NI you save on the sacrificed salary usually outweigh the BiK charge by a wide margin.

It can be particularly powerful for higher earners in the £100,000 to £125,140 band, where the personal allowance is tapered away. The sacrifice brings adjusted net income back down, helping you keep more of your personal allowance.

The catch is commitment. Salary sacrifice agreements typically run for two to four years. Leaving early because of redundancy, long-term sickness or changing jobs can trigger significant exit fees. Read the small print before signing.

Addressing Common Objections

People often hesitate before changing arrangements, and the same worries come up repeatedly. It's worth tackling them head-on.

"Won't switching scheme affect my pension contributions?" In most modern schemes, employer pension contributions are based on your full notional salary, including any sacrifice. Check your scheme rules, but the impact is usually minimal.

"What if I leave the job mid-contract?" With a company car, you simply hand back the keys. With salary sacrifice, early exit fees apply. However, most reputable providers now offer insurance that covers redundancy and long-term sickness for a small monthly add-on.

"Isn't a cash allowance always more flexible?" Flexibility is real, but it's not free. You're trading certainty and risk-free running costs for the freedom to choose a cheaper used car. Whether that trade-off is worth it depends entirely on the maths in your specific case.

Practical Steps Before You Decide

Here's a sensible order of operations. The whole exercise should take about 30 minutes if you have your paperwork to hand.

1. Get the precise figures from your employer. Ask for the P11D value, the BiK percentage for your chosen car, the cash allowance amount and the business mileage reimbursement rate.
2. Estimate your real annual mileage. Split it honestly between business and personal. Most people overestimate business mileage and underestimate personal.
3. Price up a personal lease or finance deal for an equivalent car. Include insurance with business cover, servicing, tyres and breakdown. Make sure the lease mileage allowance matches your real mileage.
4. Run both scenarios through a calculator. Our company car versus cash allowance tool compares the after-tax cost of each route side by side in under five minutes.
5. Factor in flexibility and risk. A company car removes depreciation risk and admin. A cash allowance lets you choose any vehicle, including a cheaper used one, and keep any savings.

Other ways to stretch your take-home pay

Once you've sorted the car question, look at other areas where households quietly leak money:

• Got a spare room? The Rent a Room Scheme profitability checklist shows how to earn up to £7,500 tax-free.
• Paying too much for cover? Our guide on How to Choose the Perfect Insurance Excess and Save Hundreds Every Year helps you optimise your premiums. It pairs nicely with the savings from a well-chosen car arrangement.

Common Mistakes People Make

Before you sign, double-check you're not falling into any of these traps:

• Comparing the gross cash allowance to the post-tax cost of a company car.
• Forgetting to include insurance business-use loading.
• Assuming the 45p mileage rate is the only number that matters.
• Choosing a high-emission petrol or diesel car because the BiK "doesn't look too bad" on paper.
• Picking a PHEV without checking its electric-only range against current BiK bands.
• Underestimating depreciation when buying rather than leasing.
• Failing to claim mileage allowance tax relief through Self Assessment.
• Ignoring the impact of salary sacrifice on pension contributions and statutory pay.
• Assuming workplace EV charging will always be tax-free.
• Locking into a long agreement without considering job security.

Conclusion

The honest answer is that neither a company car nor a cash allowance is universally better.

In 2026, the balance tilts towards company cars for anyone choosing pure electric who does modest business mileage. Cash allowances still make sense in two situations:

• low-mileage drivers happy to run a modest used car
• high-business-mileage drivers whose employer reimburses at or near HMRC's rates

High-emission company cars are the worst of both worlds. Meanwhile, salary sacrifice EVs sit quietly at the top of the efficiency table for most higher earners.

Don't rely on a colleague's anecdote or a friend's hunch. Sit down with your actual numbers: your tax band, your real mileage and the specific car on the table. Run them through our company car BiK vs cash allowance calculator, check the small print on insurance and grey fleet obligations, and only then sign the form. A bit of careful maths now can save you a four-figure sum every year for as long as you hold the role.

Sources

• HMRC: Tax on company cars
• HMRC: Travel — mileage and fuel rates and allowances