If your business uses a company car or salary sacrifice scheme, P11D company car reporting is one of the key deadlines in your calendar.

Every year, employers need to tell HMRC about the benefit in kind tax due on perks given to staff on top of their salary, and company cars sit right at the top of that list.

With the 6 July 2026 deadline approaching for the 2025/26 tax year, getting your P11D company car submissions right protects you from penalties and keeps your employees on the correct tax code.

To help you prepare, the SG Fleet team put together a practical guide to what you need to report, the mistakes to sidestep, and how salary sacrifice can take some of the strain off your benefit in kind tax obligations.

What does a P11D report?

A P11D is the form employers use to report taxable benefits and expenses provided to directors and employees that have not already gone through payroll.

Common examples might include:

-       Company cars

-       Private medical insurance

-       Interest-free loans

-       Living accommodation.

The form is filed once per employee who received reportable benefits, while a partner form called the P11D(b) declares the total Class 1A National Insurance the employer owes.

For company cars and salary sacrifice specifically, HMRC works out the taxable benefit in kind tax value using the car's P11D value, which is the list price including VAT, delivery, and any optional extras, multiplied by the appropriate benefit in kind percentage based on the vehicle's CO2 emissions.

This is one of the key reasons why electric vehicles have become so popular on fleets: a zero-emission car is taxed at just 4% for 2026/27, compared with rates of up to 37% for higher-emitting petrol and diesel models.

Two dates matter for your P11D this summer.

You must file your P11D and P11D(b) forms and give each employee their copy by 6 July 2026, then pay any Class 1A National Insurance, charged at 15% for 2025/26, by 22 July if you pay electronically.

Filing is online only, as paper forms are no longer accepted.

How do I report a company car on a P11D form in the UK?

Reporting a company car on a P11D form in the UK means entering the car's details in Section F of the form, covering cars and car fuel.

You’ll need:

-       The make and model

-       The date it was first made available

-       The CO2 figure

-       The fuel type

-       The P11D list price

-       The number of days the car was available during the tax year.

From there, your payroll software or HMRC's company car and car fuel benefit calculator works out the cash equivalent that becomes the taxable benefit.

Want to take the headache out of company car reporting?

SG Fleet's salary sacrifice schemes come with a full reporting suite covering payroll, P11D, and tax at source, so your team submits with confidence. Talk to our experts today.

Common P11D mistakes to avoid

Errors on P11D company car returns are not at all uncommon, and they tend to fall into a few buckets. Missing the deadline is the costly one: penalties are automatic and stack up at £100 per 50 employees for every month the return is late.

Other frequent slip-ups are usually things like using the wrong P11D value (forgetting that optional extras and VAT are included), failing to account for periods when a car was genuinely unavailable, and forgetting that a P11D(b) and Class 1A payment are still due even where benefits are payrolled.

Does salary sacrifice remove the need to submit a P11D?

The honest answer is usually no, but with an important nuance.

When a company car is provided through salary sacrifice, the benefit is still reportable, and the taxable value is calculated under the Optional Remuneration Arrangements, or OpRA, rules introduced in April 2017. Under those rules, the reportable figure is generally the higher of the normal benefit in kind value or the amount of salary the employee gave up.

The good news for EV-focused fleets is that ultra-low emission vehicles of 75g/km CO2 or less are exempt from this "higher of" comparison. For electric cars, that means the benefit is calculated using the standard low benefit in kind tax rate rather than the salary sacrificed, keeping the tax charge attractively low.

So while salary sacrifice does not eliminate the P11D obligation itself, an electric salary sacrifice scheme keeps the reportable benefit in kind tax figure small and the calculation refreshingly simple.

It’s definitely worth noting that benefits processed through payroll under voluntary payrolling do not appear on individual P11Ds, though the P11D(b) and Class 1A declaration are still required. This is the direction of travel: from April 2027, payrolling of most benefits becomes mandatory, making 2025/26 one of the last full years of traditional P11D reporting for many employers.

All of this means that starting your EV transition planning now is a smart move.

Ready to make your next P11D season the easiest yet?

At SG Fleet, we’re proud to be a multi-award-winning fleet management company and the only UK provider offering both employer-led and employee-led salary sacrifice schemes.

Whether you want to electrify your fleet with the help of our eStart transition planning service, launch a salary sacrifice scheme with built-in P11D and tax reporting, or simply get reliable data for your company car submissions, our team is here to help.

With over 25 years of UK fleet expertise and a reporting suite designed to keep you compliant, we help to reduce the complexity out of benefit in kind tax.

Get in touch with us today to find out how we can simplify your next P11D season.

FAQs

What is the P11D deadline for 2026?

The deadline to file your P11D and P11D(b) forms for the 2025/26 tax year is 6 July 2026. Any Class 1A National Insurance owed must be paid by 22 July 2026 if you pay electronically.

Do electric company cars need to go on a P11D?

Yes. Electric company cars are still reported on a P11D, but they attract a low benefit in kind tax rate of 4% for 2026/27, so the reportable value and tax charge are much lower than for petrol or diesel.

Does salary sacrifice remove the need to submit a P11D?

Generally no. A salary sacrifice company car is still reported under the OpRA rules. However, ultra-low emission and electric vehicles are exempt from the "higher of" comparison, keeping the reportable figure low.

What happens if I miss the P11D deadline?