Year-End Tax Planning: 7 Things to Do Before April 2026

April 5 is the deadline. That's your last chance to do stuff in the old tax year before everything changes on April 6. Dividends get taxed more. Savings get taxed more. Making Tax Digital launches. Homeworking relief disappears. This isn't the year to coast through tax year-end. You've got weeks to act.

1. Use Your ISA Allowance

You get £20,000 to put into ISAs. Use it or lose it on April 6. No rollover, no exceptions.

Why does this matter? Two reasons. First, dividend and savings tax both rise next year. Money in an ISA dodges that completely. Second, the cash ISA limit drops from £20,000 to £12,000 from April 2027. This is your last year to max out. After April 6 next year, the window closes.

If you've got dividend stocks or interest-bearing accounts outside an ISA, move them now. Seriously. You've got weeks.

2. Maximise Pension Contributions

Pension contributions get tax relief at your top rate. You can put in £60,000 per year (or 100% of earnings if less), and you can carry forward unused allowance from the last three years. Pensions also reduce your taxable income — they can push you below the higher-rate threshold, recover your personal allowance if you're over £100k, and lower your adjusted net income for Child Benefit calculations.

3. Check Your Tax Code

Your tax code controls how much HMRC deducts from your payslip. Wrong code means you're over/underpaying all year. Log in to your Personal Tax Account and verify it. Common problems: old benefit adjustments still attached, employment records not removed, Marriage Allowance not applied. If you've overpaid, you can claim it back through the account or call HMRC.

4. Use Your CGT Allowance

You get £3,000 in capital gains tax-free. If you've got investments with gains sitting outside an ISA, sell up to that limit before April 5. You can immediately rebuy inside an ISA (called "bed-and-ISA"). The allowance vanishes on April 6 — you can't carry it forward.

5. Claim Marriage Allowance

If one of you earns under £12,570 and the other is a basic-rate taxpayer, the lower earner can shift £1,260 of their allowance. Saves £252 a year. You can claim it on GOV.UK and backdate four years.

6. Gift Aid Donations

If you donated with Gift Aid, higher and additional-rate taxpayers can claim back the difference between your top rate and the basic rate. A £100 donation costs you effectively £60 if you're higher-rate. Claim through Self Assessment or ask HMRC to adjust your code.

7. Plan for Making Tax Digital

If you are self-employed or a landlord with qualifying income above £50,000, Making Tax Digital for Income Tax becomes mandatory from April 2026. You will need MTD-compatible software and must submit quarterly digital updates.

If you have not already, the last few months of 2025/26 are the time to:

• Choose and set up MTD-compatible software.
• Ensure your digital records are in order.
• Sign up for HMRC's testing programme.

What About Self Assessment?

The Self Assessment deadline for the 2024/25 tax year is 31 January 2026. If you have not filed yet, prioritise this — late filing triggers an immediate £100 penalty regardless of whether you owe tax.

Use the Calculator

Try our UK salary calculator to see your current take-home pay and experiment with different pension contribution levels, salary sacrifice amounts, or tax code changes before the year-end.

The Bottom Line

This isn't rocket science. ISAs, pensions, tax codes, CGT allowance — all straightforward. But they're easy to skip. And in April everything changes. Spending an hour now — literally an hour — saves hundreds over the next year. That's the trade. Do the work now or pay later.