Company Car Tax 2026: HMRC Updates for UK Fleet Managers

The risk sitting in your fleet right now

If you run a fleet and any of your employees have private use of a company car, you are already operating inside one of HMRC's most actively enforced benefit-in-kind (BIK) regimes. Get the numbers wrong on a P11D, miss a change in the appropriate percentage table, or misclassify a vehicle's CO2 emissions, and you are looking at unpaid tax, Class 1A National Insurance contributions, interest charges, and potential penalties.

The 2025/26 and 2026/27 tax years bring concrete changes to BIK rates across the board. For fleets that have not yet refreshed their tax planning, now is the time. This post sets out what the rules actually say, what your obligations are, and what compliance looks like in practice.

---

What is company car tax (BIK)?

Company car tax is formally called a benefit in kind. When an employee has a company car available for private use, that car is treated as a taxable benefit. HMRC calculates the taxable value by multiplying the car's list price (the P11D value) by an "appropriate percentage" tied to the vehicle's CO2 emissions and fuel type. The employee pays income tax on that value; the employer pays Class 1A National Insurance at 13.8% on it.

The formula is straightforward:

Taxable value = P11D value x appropriate percentage

For example: a petrol car with a P11D value of £35,000 and CO2 emissions of 120g/km sits in the 29% band for 2025/26. The taxable benefit is £10,150. A basic-rate taxpayer pays £2,030 in income tax; the employer pays £1,400.70 in Class 1A NICs.

HMRC publishes the full appropriate percentage tables each year. The tables are central to every calculation your payroll or fleet team makes.

---

What are my obligations?

Reporting via P11D

Every employer providing a company car must report the benefit to HMRC on form P11D for each affected employee by 6 July following the end of the tax year. The Class 1A NIC payment is due by 19 July (22 July if paying electronically).

Failing to file by 6 July triggers automatic penalties of £100 per 50 employees per month the form is late.

Payrolling benefits

Since April 2016, employers have been able to payroll benefits (including company cars) instead of using P11D. From April 2026, HMRC is making payrolling of benefits mandatory for most employers. This is a significant administrative change. If you are still on a P11D workflow and have not yet registered for payrolling, you need to act before the 2026/27 tax year begins on 6 April 2026.

Accurate CO2 data

The appropriate percentage is locked to the car's official CO2 figure (WLTP from April 2020 onwards for new vehicles). If your fleet records hold incorrect CO2 data, every calculation built on them is wrong. HMRC expects you to use the manufacturer's type approval figure, not an estimate.

Employee changes

If a car is withdrawn, the fuel benefit ceases, or the vehicle is replaced mid-year, you must report the change. Partial-year benefits are calculated on a pro-rata basis.

---

What happens if I get it wrong?

Penalties for incorrect P11D returns

HMRC can raise a discovery assessment going back up to four years for careless errors, or six years for deliberate errors. Penalties for careless understatement start at 30% of the potential lost tax; deliberate errors attract penalties of 70% to 100%.

Class 1A NIC interest

Unpaid Class 1A NICs accrue interest from the due date. HMRC's late payment interest rate has been above 7% in recent periods, so delays compound quickly.

PAYE compliance checks

HMRC uses employer compliance reviews to check BIK reporting. A single fleet with poorly kept mileage logs, missing CO2 data, or inconsistent P11D values can trigger a full PAYE audit covering multiple years.

---

What do the 2025/26 and 2026/27 rate changes actually mean?

Electric vehicles: the rates are rising

This is the change most relevant to fleets that have shifted toward EVs. The BIK rate for zero-emission cars (electric vehicles) has been deliberately low to drive uptake: 2% in 2023/24, 2% in 2024/25, and 3% in 2025/26. From 2026/27, the rate rises to 4%, and HMRC has confirmed it will continue to increase by 1 percentage point per year, reaching 9% by 2030/31.

For context: a £50,000 electric car generates a taxable benefit of £1,500 in 2025/26 (at 3%). In 2026/27 it becomes £2,000 (at 4%). That is a 33% increase in the benefit value in a single year. For a higher-rate taxpayer, the personal tax bill rises from £600 to £800. The employer's Class 1A NIC bill rises from £207 to £276 per car.

Multiply that across a fleet of 50 EVs and the employer NIC increase alone is roughly £3,450 per year. Not catastrophic, but not invisible either.

Search interest in "electric company car tax" on Google Trends (GB) has been rising consistently, reflecting exactly this concern among fleet managers and employees considering EV company cars (source: https://trends.google.com/trends/explore?q=electric%20company%20car%20tax&geo=GB).

Petrol and diesel: continued step-ups

Petrol and diesel appropriate percentages have been increasing incrementally. By 2026/27, the maximum appropriate percentage for high-emission vehicles reaches 37%. Cars emitting over 170g/km CO2 sit at this ceiling. If your fleet still carries older, high-emission diesel vehicles, the tax cost to employees and the NIC cost to you continues to climb.

Hybrid vehicles: the mid-range squeeze

Plug-in hybrids (PHEVs) have historically benefited from lower BIK rates tied to their electric-only range. From 2025/26 onwards, HMRC is tightening the range thresholds. Vehicles with an electric-only range below 30 miles are treated more like conventional cars. The practical effect: a PHEV that looked attractive in 2022 may now sit in a significantly higher band.

---

What does compliance actually look like?

Compliance is not a once-a-year P11D exercise. It is a continuous data discipline. Here is what it looks like when done properly.

1. Maintain a live vehicle record for every fleet car. This means P11D value (including factory options fitted at the point of sale), CO2 emissions (WLTP figure), fuel type, and date of first registration. Every field matters for the calculation.

2. Track changes in real time. When an employee leaves, when a car is replaced, when a fuel card benefit is removed: record the date. Pro-rata calculations require accurate start and end dates.

3. Communicate BIK values to employees before the tax year. Employees have a right to understand what they owe. If an employee's tax code is wrong because HMRC has the wrong BIK value, they will come to you. Getting ahead of this avoids disputes.

4. Register for payrolling of benefits before April 2026. With mandatory payrolling incoming, any fleet that has not yet migrated needs to register with HMRC before the start of the tax year. You cannot register mid-year.

5. Audit your CO2 data now. Pull your vehicle list and cross-reference CO2 figures against the DVLA vehicle enquiry service or manufacturer specifications. One wrong figure on a high-value car can mean years of incorrect reporting.

6. Check the appropriate percentage tables each April. Rates change annually. Do not carry forward last year's percentages.

---

One-glance summary

• Company car BIK is calculated as: P11D value x appropriate percentage
• P11D forms are due by 6 July each year; Class 1A NICs by 19 July (22 July electronically)
• Late P11D filing costs £100 per 50 employees per month
• From April 2026, payrolling of benefits becomes mandatory for most employers
• Electric car BIK rises from 3% (2025/26) to 4% (2026/27), then 1 point per year to 9% by 2030/31
• High-emission petrol/diesel vehicles reach a 37% appropriate percentage cap in 2026/27
• HMRC can go back 4 years for careless errors; 6 years for deliberate ones
• Penalties for understatement start at 30% of lost tax
• Keeping accurate, real-time vehicle records is the single most important control

Interest in company car tax obligations among UK businesses is measurably rising. Google Trends (GB) data for "company car tax uk" (https://trends.google.com/trends/explore?q=company%20car%20tax%20uk&geo=GB) and "hmrc company car tax" (https://trends.google.com/trends/explore?q=hmrc%20company%20car%20tax&geo=GB) both show sustained upward movement. That reflects a genuine increase in the complexity and cost of getting this right. The fleet managers who stay ahead of it are the ones with clean data, an early move to payrolling, and a clear view of what every car in their fleet costs in tax, not just in fuel.

---

This post is for general information only. It does not constitute tax or legal advice. Consult a qualified tax adviser for guidance specific to your organisation.