Published: July 2026 | Fact-Checked & Audited By: David Vance, CTA FCA (Chartered Tax Advisor & Accountant)
This guide is fully updated for the 2026/27 HMRC tax year. All calculations and tax rules have been audited against official UK legislation and statutory guidance.
When structuring compensation packages, UK employers frequently offer a choice between a company-provided car and a monthly cash car allowance. This choice is not just about convenience; it carries significant financial and tax implications. A cash allowance increases your gross salary but is fully taxed, while a company car is subject to the Benefit-in-Kind (BIK) tax regime. This guide provides a detailed analysis of the tax rules, vehicle costs, and mileage claim considerations to help you decide which option is more tax-efficient.
1. How a Cash Car Allowance is Taxed
A cash car allowance is treated by HMRC as standard salary. It is added to your earnings and subjected to PAYE Income Tax, employee National Insurance Contributions (NICs), and potentially student loan deductions. For example, if you receive a monthly car allowance of £400 (£4,800 per year):
- Gross Allowance: £4,800
- Income Tax (40% Higher Rate): £1,920
- Employee NI (2%): £96
- Net Allowance in Pocket: £2,784
This means you only receive £2,784 in cash to fund your private vehicle purchase, insurance, maintenance, and fuel. If you buy a car privately, you are responsible for all depreciation risks and repair costs.
2. The Company Car Alternative: BIK Tax Analysis
A company car does not add cash to your monthly pay. Instead, you pay Income Tax on the car’s taxable Benefit-in-Kind (BIK) value, which is based on the car’s original list price (P11D value) and CO2 emissions. If you choose an electric vehicle (EV), the BIK rate is extremely low (2%). For a £40,000 electric car, a 40% taxpayer pays just £320 in annual tax. If you choose a diesel executive car with a 32% BIK band, you pay £5,120 in annual tax. To see the BIK band details, check our guide on Company Car BIK Rates.
3. Business Mileage Claims: AMAP vs. AFR
How you claim business mileage is a major factor in this comparison:
- Private Cars (Cash Allowance): If you use your private car for business travel, your employer can pay you tax-free mileage under the Approved Mileage Allowance Payments (AMAP) scheme. The current statutory rates are 45p per mile for the first 10,000 business miles and 25p per mile thereafter. If your employer pays less than these rates, you can claim tax relief on the difference.
- Company Cars: If you drive a company-owned car, you cannot use the AMAP rates. Instead, you claim business fuel using HMRC’s Advisory Fuel Rates (AFR) or Advisory Electricity Rate (AER), which are much lower (ranging from 7p per mile for EVs to 13p-20p per mile for petrol/diesel) and are intended to cover fuel costs only.
4. Which Option Should You Choose?
To make the optimal financial decision, evaluate the following factors:
- Are you going Electric? If yes, the company car option is almost always superior due to the 2% BIK rate and corporate FYA tax breaks.
- Do you do high business mileage? If you drive over 10,000 business miles per year, taking the cash allowance and claiming the tax-free 45p mileage allowance often yields enough cash to pay for the car’s running costs.
- Do you want hassle-free driving? Company cars generally include fully funded insurance, road tax, servicing, and tyres paid for by your employer. A cash allowance leaves all maintenance responsibility and financial risks with you.
5. Frequently Asked Questions (FAQs)
Q: Does my employer pay National Insurance on my car allowance?
A: Yes. Cash allowances are subject to Employer Class 1 National Insurance Contributions (currently 13.8%), whereas company cars are subject to Class 1A NI.
Q: Can I use a car allowance to finance a personal car lease (PCP)?
A: Yes. The cash is paid directly to you, and you are free to spend it on PCP, Hire Purchase, leasing, or buying a vehicle outright.