A surprising number of owner-managed business owners encounter the P11D for the first time only when their accountant mentions it at year end — or worse, when HMRC writes to ask why one has not been filed. So if you are asking what is a P11D, you are in good company.

Put simply, a P11D is the form an employer uses to tell HMRC about benefits and expenses provided to employees or directors that have not been put through payroll. Think company cars, private medical insurance, interest-free loans, gym memberships, or any other non-cash perk with a monetary value. If you run a limited company and pay yourself partly through perks rather than salary, the P11D is almost certainly relevant to you.

In this post we will walk through exactly what the P11D covers, who needs to file it, what the deadlines are for the 2025/26 tax year, and — importantly — what is about to change with mandatory payrolling from April 2027.

The P11D is a statutory form that reports benefits in kind — that is, any non-cash benefit or expense with a taxable value that an employer provides to an employee or director. HMRC uses the information to calculate the additional Income Tax the employee owes, and the employer owes Class 1A National Insurance Contributions (NICs) on the value reported.

Common benefits that typically appear on a P11D include:

• Company cars and fuel — valued using the car’s list price multiplied by a CO2 emissions percentage set by HMRC each year
• Private medical or dental insurance — the cost of the premium paid by the employer
• Beneficial loans — interest-free or low-interest loans above £10,000
• Living accommodation provided by the employer
• Gym memberships and other non-business subscriptions

Not everything is taxable. There are exemptions and trivial benefit rules (for gifts up to £50, for example) that can legitimately keep certain perks off the form. But the default position is: if you are paying for something for an employee or director that is not purely business-related, it probably needs to be reported.

It is worth distinguishing the P11D from the P11D(b). The P11D is filed per employee; the P11D(b) is the employer’s declaration of the total Class 1A NICs due on all those benefits. Both have the same deadline, and both carry penalties if missed.

Any employer — including the director of a one-person limited company — who has provided taxable benefits to employees or directors during the tax year needs to file a P11D for each person who received those benefits.

This is where many owner-managed business owners get caught out. If you are the sole director of your limited company and the company pays for your private health insurance or provides you with a company car, the company is technically the employer and you are the employee. That means a P11D is required for you personally, even if you are the only person who runs the business.

You do not need to file a P11D if:

• You have already payrolled the benefit — that is, included its cash equivalent value in the employee’s monthly payroll and deducted tax through PAYE in real time
• The benefit falls within an exempt category or a HMRC-approved dispensation
• No taxable benefits were provided at all during the year

If you are unsure whether something you provide counts as a benefit in kind, the safest approach is to check before the year end rather than after. Discovering a missed P11D obligation after the deadline rarely ends well, and HMRC does not tend to accept ‘I did not know’ as a reasonable excuse for late filing.

For the 2025/26 tax year, both the P11D and the P11D(b) must be filed with HMRC by 6 July 2026. Any Class 1A NICs owed on the benefits reported must be paid by 19 July 2026 (or 22 July if paying electronically).

The Class 1A NIC rate for 2025/26 is 15% of the total taxable value of benefits reported on the P11D(b).

Missing the deadline carries real consequences:

• For a late P11D(b), HMRC charges an automatic penalty of £100 per 50 employees (or part thereof) for each month or part-month the form is late — so even a small employer will receive a penalty notice quickly.
• For a late individual P11D, penalties of up to £300 per form can be charged, with further daily penalties of £60 if a tribunal approves.
• Interest will also accrue on any unpaid Class 1A NICs from the payment deadline.

In our experience, employers who miss P11D deadlines are usually those who did not realise they had an obligation in the first place — not those who knew and chose to ignore it. Getting clarity on what you need to report, and when, before the year end is the most effective way to avoid this situation entirely.

This is the big shift on the horizon, and it is worth understanding now even if the deadline feels distant.

From April 2027, HMRC will require most benefits in kind to be reported and taxed through payroll in real time — rather than via an annual P11D form after the tax year ends. This is known as mandatory payrolling of benefits, and it effectively replaces the P11D process for the majority of employers.

Instead of tallying up the value of benefits provided over the year and submitting a form in July, employers will need to calculate the taxable value of each benefit each month and include it in the employee’s payroll run. The tax is then deducted at source, just like salary.

A couple of exceptions will remain outside mandatory payrolling — employer-provided living accommodation and beneficial loans will still need to be reported separately — but for most common benefits like company cars and private medical cover, the annual P11D will become a thing of the past.

Voluntary payrolling has been available since 2016, and some employers have already made the switch. If you have not, April 2027 is not as far away as it sounds. Setting up payrolling of benefits requires changes to your payroll software and processes, and it is much less stressful done thoughtfully in advance than scrambled through in March 2027.