A P11D(b) is an employer declaration form submitted to HMRC that summarises the total Class 1A National Insurance contributions due on all employee benefits and expenses for the tax year.
Key Facts: P11D(b) at a Glance
- What it is: Your annual declaration of the total Class 1A National Insurance you owe on employee benefits.
- How it links to the P11D: Each P11D reports one employee’s benefits. The P11D(b) adds them up into a single Class 1A total.
- Who files it: Any employer who submits P11Ds, payrolls benefits, or gets a request from HMRC.
- Filing deadline: 6 July after the tax year ends (6 July 2027 for 2026/27).
- Payment deadline: 22 July if paying electronically, or 19 July by post.
- What’s changing: Mandatory payrolling is being phased in from April 2027 (cars, fuel, vans and medical benefits) and April 2028 (most others). Class 1A on those benefits moves to your monthly payroll.
If you’re a business owner or HR manager, you’re probably familiar with the term P11D(b). But in true payroll fashion, they can be difficult to get to grips with.
And not only that, but there are also some legislative changes fast approaching in 2027 that will affect how you use P11D(b)’s, making it vital to get up to speed today. So, grab your coffee and let’s get to know P11D(b)s better.
What is a P11D(b) form?
A P11D(b) form is a document used for reporting expenses and benefits provided to employees by their employers. It’s an essential part of the annual tax process for businesses that offer perks beyond salaries, such as:
- company cars
- private medical insurance
- gym memberships
- beneficial loans over £10,000
- living accomodation
The “b” in P11D(b) refers to the employer’s declaration of these benefits to HMRC. Essentially, it’s the employer’s responsibility to calculate the cash equivalent value of each benefit and report it on the P11D(b) form.
The cash equivalent value of each benefit is worked out and reported for each employee on their P11D (or through payroll, if you payroll benefits). The P11D(b) then brings it all together, declaring the total Class 1A NICs you owe on those benefits.
This form helps HMRC check that employers are paying the right amount of Class 1A National Insurance contributions on their benefits and expenses. Class 1A NICs are employer-only contributions, paid at 15% on the cash equivalent value of taxable benefits. It’s important to complete and submit the P11D(b) accurately to avoid potential penalties.
What's the difference between a P11D and a P11D(b) form?
A P11D form is used by employers to report individual benefits provided to employees, such as company cars or health insurance.
But a P11D(b) is an employer declaration form that provides the total amount of Class 1A National Insurance contributions due on all benefits provided to employees.
While both forms relate to reporting benefits and expenses, the P11D details individual benefits, whereas the P11D(b) declares the employer’s overall liability for NICs on those benefits.
| Aspect | P11D | P11D(b) |
|---|---|---|
| Purpose | Reports individual employee benefits | Declares total Class 1A NICs due |
| Who completes it | Employer (per employee) | Employer (one form for all employees) |
| What it reports | Cash equivalent of each benefit per employee | Total NIC liability on all benefits |
| Deadline | 6 July | 6 July |
Who needs to submit a P11D(b)?
You must submit a P11D(b) if you’re an employer who:
- has submitted P11D forms for any employees
- payrolls benefits in kind for employees
- has been asked by HMRC to file a P11D(b)
Even if you payroll all your benefits, you’ll still need to submit a P11D(b) for the 2026/27 tax year to declare your Class 1A NIC liability. That’s because, until April 2027, Class 1A on payrolled benefits is still worked out and paid after the end of the tax year.
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What do you need to do to submit a P11D(b)?
You submit your P11D(b) online after the end of the tax year, either through HMRC’s PAYE Online service or through your payroll software, in the same way as your P11D forms. HMRC no longer accepts paper P11D(b) forms.
What is the due date for P11D(b) form submissions?
You need to submit your P11D(b) by 6 July following the end of the tax year (e.g. 6 July 2027 for the 2026/27 tax year). You must also pay your Class 1A NICs by 22 July if paying electronically, or 19 July if paying by post.
Missing these deadlines can result in penalties from HMRC:
- Late P11D(b) submission: £100 per 50 employees for each month (or part month) the form is late
- Late Class 1A NIC payment: 5% penalty after 30 days, an additional 5% after 6 months, and a further 5% after 12 months
Changes to P11D(b) from 2027
Payrolling of benefits in kind is becoming mandatory, but it’s being brought in over two years rather than all at once:
- From 6 April 2027: Payrolling becomes mandatory for company cars, car fuel, vans, van fuel, and medical and dental benefits.
- From 6 April 2028: Most remaining benefits in kind come into the mandatory regime.
- Loans and living accommodation: These stay outside the mandatory rules for now. You can choose to payroll them, but you’ll need to register with HMRC first. Registration opens in November 2026 and closes on 5 April 2027.
The biggest change for the P11D(b) is that Class 1A NICs on payrolled benefits will be reported and paid in real time through your monthly payroll submissions, rather than once a year. So, for those benefits, you won’t need a P11D or a P11D(b). Over time, the P11D(b) will only be needed for loans and accommodation that you haven’t payrolled.
It’s worth planning for the 2027/28 overlap, though. In July 2027, you’ll still pay Class 1A on your 2026/27 benefits through the P11D(b) as usual, while also paying Class 1A in real time on phase one benefits from April 2027. That’s two lots of Class 1A in the same year, which can catch cash flow out if you’re not expecting it.
Read more about the upcoming changes here: Payrolling of Benefits in Kind to Become Mandatory from 2027
Are you ready for the switch to payrolling benefits?
Due to this change, it’s likely a good idea to look at what your payroll software or service can do now. This way, if you’re working with software or process which doesn’t allow for payrolled benefits, you have time to change to a more modern product ahead of the deadline!
Here at Cintra, our payroll software and outsourced payroll services are built to handle payrolling benefits. We’re also offering all our customers a payrolling benefits service—we’ll help you through the process and make sure you’re well-prepared for when it becomes a mandatory requirement.
Payroll Legislation Guide
The facts, figures, thresholds and allowances for 2025/26 spanning tax, National Insurance, pensions, statutory payments and more.
