Last updated: April 2026.
Why end of tax year planning matters
UK tax law gives every individual a set of annual allowances, pots of tax-free or tax-advantaged activity you can use each year. Most of these are use-it-or-lose-it. If 6 April arrives and you haven't used your ISA allowance, your CGT annual exempt amount, or your annual gift exemption, those allowances vanish.
For many people, the end of tax year window is the most consequential 2–3 weeks of the year for personal tax planning. Five minutes of work can be worth thousands of pounds.
At a glance: the use-it-or-lose-it allowances
| Allowance | Amount (2025/26) | Carry-forward? |
|---|---|---|
| ISA allowance | £20,000 | No, resets to £20,000 on 6 April |
| Junior ISA allowance | £9,000 per child | No |
| Pension annual allowance | £60,000 (most people) | Yes, up to 3 prior years |
| CGT annual exempt amount | £3,000 | No |
| Dividend allowance | £500 | No |
| Personal savings allowance | £1,000 (basic) / £500 (higher) / £0 (additional) | No |
| Annual gift exemption (IHT) | £3,000 | Yes, one prior year only |
| Small gifts exemption (IHT) | £250 per person | No |
| Marriage Allowance transfer | £1,260 | Backdate up to 4 tax years |
The checklist: what to do before 5 April
1. Use your ISA allowance
Pay up to £20,000 across Cash, Stocks and Shares, and Innovative Finance ISAs. From 6 April 2027, the Cash ISA portion will be capped at £12,000 for under-65s, but for 2025/26 you can still use the full £20,000 in cash if you wish. See our guide to the 2027 ISA changes.
2. Top up your pension
Higher and additional-rate taxpayers benefit most. A £10,000 net contribution from a higher-rate taxpayer typically results in £16,667 added to the pension pot once tax relief is accounted for. Use any unused annual allowance from the previous three tax years through carry-forward, particularly powerful if you've had bonus income or variable earnings.
Critical: the contribution must arrive at your provider by 5 April. Allow 3 working days for the transfer.
3. Use your Capital Gains Tax annual exempt amount
The first £3,000 of capital gains in 2025/26 is tax-free. If you have appreciated investments outside an ISA or pension, consider realising a gain up to that limit. A common move is bed and ISA, sell the investment to crystallise the gain, then immediately repurchase inside an ISA, so future growth becomes tax-free too.
4. Use your spouse's allowances
Transfers between spouses (and civil partners) are CGT-free and IHT-free under the inter-spousal exemption. If one of you has unused ISA/CGT/dividend allowances and the other is at risk of losing theirs, restructuring jointly-held investments before 5 April can save tax across the household.
5. Make use of gifting allowances
For IHT planning:
- Annual gift exemption: £3,000 per donor per year. Can be carried forward one year if unused, so a couple who has used neither this year or last can gift £12,000 between them in March/April
- Small gifts exemption: £250 per recipient, unlimited recipients
- Wedding gifts: £5,000 to a child marrying, £2,500 to a grandchild, £1,000 to anyone else
- Gifts out of normal income: regular gifts that don't affect your standard of living, unlimited amount, immediately outside your estate, but you need a paper trail
6. Consider Marriage Allowance
If one spouse earns under the personal allowance (£12,570) and the other is a basic-rate taxpayer, the lower earner can transfer £1,260 of unused personal allowance to the higher earner, saving up to £252 of tax per year. Claims can be backdated up to four tax years if you've missed them before.
7. Charitable donations
Higher and additional-rate taxpayers can claim extra Gift Aid relief through Self Assessment, with the option to carry-back this year's donations to the previous tax year if you claim before submitting that year's return. Useful if a current-year donation would push you below a higher-rate band threshold. See our tax-efficient giving guide.
8. Pay self-employment expenses early if you have them
If you're self-employed and your profits are pushing you into higher tax brackets, accelerating allowable expenses into the current tax year (e.g. equipment purchases, professional subscriptions) can reduce your tax bill.
9. Crystallise pension lump sum (if appropriate)
If you're already at pension access age and have a strategic reason to take some tax-free cash, doing it before vs after 5 April can shift the income-tax timing on any taxable portion. This is highly individual, take advice before acting.
10. Review the bigger picture
End of tax year is also a good moment to check the things that compound over multiple years: pension nominations up to date? Wills reviewed? Lasting Powers of Attorney in place? See why estate planning matters.
The realistic timeline
Allow at least two weeks before 5 April to act on anything that involves moving money, bank transfers, ISA top-ups, pension contributions. Providers can get busy at year-end, and last-minute payments occasionally fail.
Frequently asked questions
Why does the UK tax year end on 5 April?
It's a historical quirk dating back to a calendar change in 1752. The tax year was previously a quarter-day-based system, and it shifted to 6 April when the calendar was modernised. It has never been changed since.
If I miss the deadline, can I catch up next year?
Some allowances roll forward (pension annual allowance has 3 years' carry-forward). Most do not, ISA, CGT annual exempt amount, dividend allowance, personal savings allowance, and gifting allowances all reset to zero on 6 April and unused amounts are lost.
Can I make pension contributions after 5 April that count for the previous tax year?
No. The contribution must be received by your pension provider on or before 5 April to count for that tax year. Bank transfers can take 1–3 working days, so leave time.
Do I need to do anything if I only have a workplace pension?
Workplace pension contributions via salary sacrifice happen automatically, no end-of-year action needed. Personal contributions (e.g. one-off top-ups) do need to be made before 5 April.
Does the deadline differ in Scotland?
The tax year dates are the same UK-wide. Income tax rates differ in Scotland, which affects pension tax relief calculations slightly, but the 5 April deadline is identical.