Tax Year End Checklist UK: 7 Things to Do Before 5 April 2026

Last updated: 30 March 2026

The 2025/26 tax year ends at midnight on 5 April 2026. Once it does, several valuable allowances and reliefs disappear for good. Whether you are an investor, a saver, a homeowner, or self-employed, there are practical steps worth ticking off before the deadline. This tax year end checklist covers the seven most important ones.

Disclaimer: This is not financial advice. Tax rules can change, and their effects vary based on individual circumstances. Always do your own research or consult a qualified financial adviser or accountant before making decisions.

1. Use your £20,000 ISA allowance

Every UK adult gets a £20,000 annual ISA allowance. Contributions inside an ISA are free from income tax, capital gains tax, and dividend tax. The allowance is use-it-or-lose-it, so anything you do not contribute by 5 April is gone permanently.

This year carries extra weight because the Cash ISA allowance is dropping to £12,000 for under-65s from April 2027, and dividend tax rates are rising from 6 April 2026. Sheltering investments inside an ISA before the deadline protects them from both changes.

If you have not opened a Stocks and Shares ISA yet, most platforms let you set one up in minutes. For a full comparison of the best options, see our best investment ISA 2026 guide. For deadline-specific tips, our ISA allowance deadline page has the detail.

Compare the best ISAs

2. Top up your pension

The annual pension allowance for 2025/26 is £60,000 (or 100% of your earnings, whichever is lower). Basic-rate taxpayers get 20% tax relief added automatically, while higher-rate taxpayers can claim back an additional 20% through self-assessment. Additional-rate taxpayers can claim up to 25% more.

If you have unused pension allowance from the previous three tax years, you may be able to carry it forward. This can be especially valuable for higher earners who had a good bonus year or a windfall. Both Freetrade and J.P. Morgan Personal Investing offer SIPPs alongside their ISAs.

3. Use your £3,000 capital gains allowance

The capital gains tax (CGT) annual exempt amount is just £3,000 for 2025/26. This means any gains above that threshold are taxable at 18% (basic rate) or 24% (higher rate) for most assets. If you hold investments outside an ISA that have unrealised gains, you could consider selling enough to crystallise up to £3,000 in profit before 5 April, then reinvesting afterwards.

Alternatively, if you have investments with losses, harvesting those losses before the tax year ends can offset gains elsewhere. This is sometimes called "bed and ISA" when you sell, crystallise the loss or gain, and repurchase inside an ISA wrapper.

4. Plan for the dividend tax rise

From 6 April 2026, dividend tax rates increase by 2 percentage points. The basic rate moves from 8.75% to 10.75%, and the higher rate from 33.75% to 35.75%. The dividend allowance stays at just £500. If you hold dividend-paying shares or funds outside an ISA, moving them inside the wrapper before the deadline means future dividends are completely tax-free.

For a full breakdown of what the rise means and who is affected, see our dividend tax rise April 2026 UK guide.

5. Check your marriage allowance

If you are married or in a civil partnership and one of you earns less than the personal allowance (£12,570), the lower earner can transfer up to £1,260 of their unused allowance to the higher earner. This reduces the higher earner's tax bill by up to £252 per year. You can backdate claims for up to four years through GOV.UK.

6. Contribute to a Junior ISA

If you have children, each child has a separate Junior ISA allowance of £9,000 per year. This does not count towards your own £20,000 adult ISA allowance. Contributions from parents, grandparents, and family friends all count, and the money grows tax-free until the child turns 18.

Both J.P. Morgan Personal Investing and several other platforms offer Junior ISAs. Starting early and contributing consistently can make a meaningful difference over 18 years of compound growth.

7. Make a note of what is changing from April 2026

Several changes take effect from 6 April 2026 that are worth planning for now:

Dividend tax rates rise by 2% at the basic and higher rates.
Capital gains tax on Business Asset Disposal Relief (BADR) increases from 14% to 18%.
Making Tax Digital for Income Tax becomes mandatory for self-employed individuals and landlords with qualifying income over £50,000 (dropping to £30,000 from April 2027).
Working from home allowance (£6/week without receipts) is being removed.
Employer National Insurance increased to 15% from April 2025 and remains at that level.

And looking further ahead, from April 2027 the Cash ISA allowance drops to £12,000 for under-65s, and savings tax rates rise by 2% across all bands. Knowing what is coming helps you make better decisions now.

FAQs: tax year end checklist

When does the 2025/26 tax year end?

At midnight on 5 April 2026. The 2026/27 tax year begins on 6 April 2026.

Can I still do something useful if I only have a few days left?

Yes. Even depositing cash into an ISA secures your allowance. You do not need to invest it immediately. Likewise, pension contributions and capital gains planning can be done right up to the deadline, though it is wise to allow time for bank transfers to clear.

Do I need to file anything by 5 April?

Not usually. The self-assessment filing deadline for the 2025/26 tax year is 31 January 2027 (online). However, ISA and pension contributions must be made before 5 April to count for this tax year.

Is this checklist relevant if I am employed and do not invest?

Potentially, yes. The marriage allowance, Cash ISA, and pension top-up points apply to most working adults. Even basic-rate taxpayers benefit from tax-free savings and pension relief.

Capital at risk. The value of your investments can go down as well as up, and you may get back less than you invest. Tax treatment depends on individual circumstances and may change. This article is not financial advice.