Tax Year End Checklist 2025/26: 9 Things to Do Before 5 April

Two weeks. That's all you've got before the 2025/26 tax year closes on 5 April.

Some of the allowances you're entitled to this year? They vanish at midnight. No carrying forward, no extensions, no "I'll do it next month." Gone.

Here's what's worth checking off before the deadline.

1. Use your ISA allowance (£20,000)

This one catches people out every year. You can put up to £20,000 into ISAs during the 2025/26 tax year — cash ISAs, stocks and shares ISAs, or a mix. Any amount you don't use by 5 April is lost forever. It doesn't roll over.

Even if you only have a few thousand sitting in a current account earning nothing, moving it into a cash ISA takes ten minutes and means the interest is tax-free.

2. Check your dividend planning

The dividend allowance for 2025/26 is just £500. That's the amount of dividend income you can receive tax-free before HMRC wants their cut. If you're a director of a limited company, you've probably already used this up.

But here's the thing most people miss: the timing of when you declare a dividend matters, not when the cash hits your bank account. A dividend declared on 3 April sits in the 2025/26 tax year. Declare it on 7 April and it's in 2026/27. Get your board minutes right.

If you're still working out the most tax-efficient split between salary and dividends, have a play with the numbers first.

3. Make pension contributions count

Pension contributions are still one of the best ways to reduce your tax bill. As a basic rate taxpayer, every £100 you put into a pension only costs you £80 — the government tops up the rest. Higher rate taxpayers can claim back even more through their self assessment.

For company directors: employer pension contributions are a deductible business expense too. A well-timed contribution before 5 April reduces both your personal tax and your company's corporation tax liability in one move.

The annual allowance for pension contributions in 2025/26 is £60,000, and you can carry forward unused allowance from the three previous years if you haven't maxed them out.

4. Time your capital expenditure

Bought a laptop in March? That expense reduces your taxable profit for 2025/26. Planning to buy one in April? That's next year's tax return.

If you've been putting off equipment purchases, software subscriptions, or office furniture, spending before 5 April means you'll see the tax benefit sooner. Annual Investment Allowance (AIA) lets you deduct the full cost of qualifying items up to £1 million.

Not a huge consideration for most small businesses, but if you're sitting on a £3,000 equipment purchase and you're profitable this year, the maths speaks for itself.

5. Review your salary vs dividends mix

If you run a limited company, the employer NIC rate for 2025/26 is 15% on earnings above the secondary threshold (which dropped to just £96/week this year — down from £175). That change means taking a higher salary is more expensive for your company than it was last year.

For most small company directors, the tax-efficient salary sits around the personal allowance level (£12,570) or the NIC primary threshold. Above that, dividends are usually cheaper. But everyone's situation is different — especially if you have other income sources.

6. Sort your records before they go stale

Nobody enjoys bookkeeping. But reconciling your bank transactions, filing receipts, and tidying up your accounts is far easier when the year has just ended than when you're scrambling in January.

Spend an hour this week getting your records up to date. Future you will be grateful.

7. Check if MTD affects you from 6 April

This is a big one. Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) finally kicks in from 6 April 2026 for sole traders and landlords earning over £50,000 a year.

If that's you, you'll need MTD-compatible software and you'll need to start sending quarterly updates to HMRC instead of a single annual tax return. The first quarterly deadline will come around faster than you think.

Not sure if you're ready? Worth checking now rather than finding out the hard way.

8. Claim the marriage allowance if you haven't already

If you're married or in a civil partnership and one of you earns less than £12,570, you can transfer £1,260 of their unused personal allowance to the higher earner. That's a tax saving of up to £252 for the 2025/26 year.

You can also backdate claims for up to four years. So if you've never claimed, you could be owed over £1,000 in total. Takes about five minutes on GOV.UK.

9. Don't forget Gift Aid

If you've made charitable donations this year and you're a higher rate taxpayer, you can claim back the difference between the basic rate and your rate through self assessment. A £100 donation to a Gift Aid registered charity means £25 in tax relief for a 40% taxpayer.

Timing matters here too — donations made before 5 April count for the 2025/26 tax year. You can also elect to carry back donations to the previous year if it helps.

The short version

Most of these take less than an hour each. Some take five minutes. But they all have the same deadline — and once 5 April passes, the opportunity is gone.

If you've got a limited company, the dividend and pension planning alone could save you thousands. If you're a sole trader, the MTD change on 6 April is the one to pay attention to right now.

Either way, don't leave it to the last day.