Tax Year 2024/25 Calendar: Allowances, Self Assessment, and Employer Deadlines

The 2024/25 UK tax year runs from 6 April 2024 to 5 April 2025, and the key dates and deadlines for that year stretch from allowance resets on the closing day through to the final Self Assessment payment on 31 January 2026.¹ Most filing and payment obligations fall after the year closes, but a handful of the most valuable dates sit inside it. Miss them and the allowance is gone; miss the ones after, and penalties start accumulating.

Deadlines Before the Tax Year Ends

Three annual allowances reset at midnight on 5 April 2025 and cannot be carried into 2025/26. If you want to use them, the money has to move before then.

ISA Allowance: 5 April 2025

You can save or invest up to £20,000 across your ISAs in 2024/25. That total can go into a single ISA or be split across different types, though no more than £4,000 can go into a Lifetime ISA.² Any unused portion vanishes on 6 April.

Pension Annual Allowance: 5 April 2025

The standard pension annual allowance for 2024/25 is £60,000, covering your own contributions, employer contributions, and government tax relief combined. If your adjusted income exceeds £260,000, the allowance tapers by £1 for every £2 above that figure, down to a minimum of £10,000.³ Contributions above the allowance are taxed as income, so check the running total before year-end.

Capital Gains Tax Exempt Amount: 5 April 2025

The CGT annual exempt amount for 2024/25 is £3,000 per person, down from £6,000 the previous year and £12,300 the year before that.⁴ Selling assets with modest gains before 5 April 2025 uses this year’s exempt amount; the 2025/26 amount resets independently.

Self Assessment Deadlines After 5 April 2025

Self Assessment applies if you are self-employed, a company director, a higher-rate taxpayer with investment income, or anyone else with income not fully taxed at source. Four dates matter for the 2024/25 return:

5 October 2025 — deadline to register with HMRC if you have not filed a return before, or if you did not need to file for 2023/24.⁵
31 October 2025, 11:59 pm — paper returns must reach HMRC.⁵
31 January 2026, 11:59 pm — online returns must be submitted.⁵
31 January 2026 — any tax owed for 2024/25 must be paid.⁵

Paper and online filing are separate channels with separate deadlines. If you miss 31 October on paper, you cannot switch to online filing to buy more time.

Payments on Account

If your Self Assessment bill is more than £1,000 and less than 80% of your tax was collected at source through PAYE, HMRC requires payments on account toward the following year. Each payment equals half of your previous year’s bill:

31 January 2026 — first payment on account for 2025/26, due alongside any balance owed for 2024/25
31 July 2026 — second payment on account for 2025/26⁵

The January date catches people off guard because it combines the balancing payment for the year just ended and the first instalment toward the year ahead. If your income has dropped, you can apply to reduce your payments on account, but reduce too far and HMRC charges interest on the shortfall.

What Happens If You Miss the Deadlines

Late filing triggers an escalating structure that runs regardless of whether tax is owed:

1 day late: £100 fixed penalty
3 months late: daily penalties of £10 per day for up to 90 days, totalling £900
6 months late: a further 5% of the tax due or £300, whichever is greater
12 months late: another 5% of the tax due or £300, whichever is greater⁶

Late payment carries separate penalties on top. HMRC charges 5% of the unpaid tax at 30 days, 6 months, and 12 months, plus interest for the entire period the tax remains unpaid.⁶ Someone six months late and still not paid can face well over £1,000 in combined penalties before interest is counted. Filing on time with an estimated figure and correcting later is almost always better than missing the deadline while waiting for perfect numbers.

60-Day CGT Deadline on Residential Property

Selling a UK residential property at a gain triggers its own clock that sits outside the Self Assessment calendar. You must report the disposal and pay any CGT due within 60 days of the completion date.⁷ Have the original purchase price, selling costs, and qualifying improvement expenditure ready as soon as the sale completes. The gain still goes on your Self Assessment return if you file one, and CGT already paid through the 60-day report is credited against the final bill.

Gains from shares, personal possessions worth over £6,000, and other chargeable assets go through Self Assessment by 31 January 2026 in the normal way. There is no separate 60-day requirement for non-residential disposals.⁵

Employer Deadlines Through and After the Year

PAYE Every Month

Employers must send deducted income tax and National Insurance to HMRC on a strict monthly cycle:

By cheque through the post: payment must reach HMRC by the 19th of the following month
Electronically: payment must clear by the 22nd of the following month⁸

Small employers whose average monthly PAYE liability is below £1,500 can pay quarterly instead. Quarterly payments are due on the 22nd after the quarter ends (or the 19th by cheque), so 22 July for the quarter running 6 April to 5 July.⁸

P60s by 31 May 2025

Every employee on your payroll on 5 April 2025 must receive a P60 summarising their pay and deductions by 31 May 2025.⁹ Employees need it for mortgage applications, Self Assessment returns, and tax credit claims.

P11D and Class 1A NIC by July 2025

If you provided expenses or benefits such as company cars, private medical insurance, or interest-free loans, you must submit P11D forms and a P11D(b) to HMRC by 6 July 2025 and give employees their P11D copies by the same date. Class 1A National Insurance on those benefits is due by 22 July 2025 electronically, or 19 July 2025 by cheque. A late P11D(b) attracts £100 per 50 employees for each month or part-month overdue.¹⁰

2024/25 Tax Calendar at a Glance

6 April 2024 — tax year begins
5 April 2025 — tax year ends; last day for ISA, pension, and CGT allowances
31 May 2025 — employers issue P60s
6 July 2025 — P11D submission and employee copies
22 July 2025 — Class 1A NIC payment (19 July by cheque)
5 October 2025 — register for Self Assessment if filing for the first time
31 October 2025 — paper Self Assessment return
31 January 2026 — online Self Assessment return, 2024/25 tax payment, and first payment on account for 2025/26
31 July 2026 — second payment on account for 2025/26

Residential property CGT follows its own 60-day clock from the completion date and sits outside this schedule. PAYE remittances recur every month (or quarterly for eligible small employers) on the 19th or 22nd depending on payment method.⁸

1
Legislation.gov.uk. Income Tax Act 2007 – Section 4
2
GOV.UK. Individual Savings Accounts (ISAs) – How ISAs Work
3
GOV.UK. Tax on Your Private Pension Contributions – Annual Allowance
4
GOV.UK. Capital Gains Tax Rates and Allowances
5
GOV.UK. Self Assessment Tax Returns – Deadlines
6
GOV.UK. Self Assessment Tax Returns – Penalties
7
GOV.UK. Report and Pay Your Capital Gains Tax – If You Sold a Property in the UK on or After 6 April 2020
8
GOV.UK. Pay Employers’ PAYE – Overview
9
GOV.UK. Payroll Annual Reporting and Tasks – Give Employees a P60
10
GOV.UK. Expenses and Benefits for Employers – Deadlines