P11D Deadline 6 July 2026: What to File, Class 1A Dates, and the Penalties

The Three Dates That Matter

Filing is online only — paper P11Ds were abolished. Submit through your payroll software or HMRC's PAYE Online service.

Do You Even Need to File?

You need a P11D for anyone who received benefits in 2025/26 that weren't already taxed through payroll. For a typical small limited company the usual suspects are:

• Private medical or dental insurance paid by the company — the most common director benefit
• Company cars and fuel — though fully electric cars at 3% BiK remain cheap
• Beneficial loans — a director's loan account that exceeded £10,000 at any point in the year, charged below HMRC's official rate. If your DLA was overdrawn past that line even briefly, check the position now
• Gym memberships, non-trivial gifts, personal bills paid by the company

What you don't report: pension contributions, one mobile phone, trivial benefits under £50, and anything you already payroll. Business expenses reimbursed under the exemption (travel, subsistence) don't belong on a P11D either — the full list is here.

The nil-return trap: if HMRC has sent you a notice to file a P11D(b) — usually because you filed one last year — you must submit either the return or a declaration that no benefits were provided. Ignore it and the penalties run automatically even though you owe nothing.

What It Costs to Get It Wrong

Late P11D(b): £100 per 50 employees (or part thereof) per month. For a small company that's £100/month, every month, until you file — a six-month delay is £600 for a form that takes an hour.

Late Class 1A payment: 5% of the unpaid NIC at 30 days, another 5% at six months, another 5% at twelve months — plus late-payment interest at 7.75% running the whole time.

Incorrect returns: penalties up to £3,000 per form for careless or deliberate errors. If you spot a mistake after filing, submit a corrected version — flagging it yourself is the difference between no penalty and a charged one.

The Class 1A Bill: A 90-Second Calculation

Class 1A is the employer-only NIC on benefits: 15% of the total cash equivalent reported across your P11Ds (the rate matching employer NI since April 2025). One director with £1,800 of private medical cover means a Class 1A bill of £270, payable by 22 July. Use the right payment reference — your Accounts Office reference plus the digits 2613 (tax year 2026, month 13) — or HMRC's systems will allocate it against regular PAYE and chase you for the "missing" Class 1A.

This Is (Almost) the Last P11D

From 6 April 2027, payrolling benefits in kind becomes mandatory: most benefits will be reported and taxed through payroll in real time, with Class 1A calculated and reported in-year. The annual P11D round disappears for everything except employment-related loans and living accommodation, which are carved out for now (the move was delayed from 2026).

What that means practically: this summer you file for 2025/26; next summer you file for 2026/27; then the system changes. If you'd rather payroll voluntarily for 2027/28 before being forced to, HMRC's registration service opens in November 2026 — and note it's already too late to payroll for 2026/27, since registration closed before 6 April 2026.

Get It Done This Week, Not on 5 July

Everything you need is in your books: insurance invoices, car lease agreements, your director's loan account balance through the year. Pull them together, file online, set the Class 1A payment for 22 July, and diary the same job for next year — the last time you'll ever do it.

If your receipts and bank feeds already live in AccountsOS, Finn can list every payment that looks like a benefit in kind for 2025/26 in one question — "what did the company pay for that might need a P11D?" — and your deadlines page tracks 6 July and 22 July automatically.