Year-End Tax Planning 2025-26: What to Review After 5 April

The 2025 to 2026 tax year ended on 5 April 2026.

That means the last-minute ISA, pension, Capital Gains Tax, dividend, and savings allowance window for that tax year has closed. But the article is still useful if you read it the right way: as a post-year-end review and a planning checklist for the tax year now under way.

The main task now is to check what can still be claimed, what needs to be reported, and what you should set up early for 2026 to 2027.

Quick Summary

• The 5 April 2026 deadline for most 2025 to 2026 use-it-or-lose-it allowances has passed.
• You cannot usually make a new ISA subscription or CGT disposal count for a tax year after it has ended.
• Some actions still matter after year end, including Self Assessment, Marriage Allowance backdating, tax-code checks, and pension carry-forward planning.
• The 2026 to 2027 ISA limit is £20,000 and the pension annual allowance is £60,000, subject to tapering and other restrictions.
• PAYE workers should check whether side income, dividends, savings interest, or relief claims need reporting outside payroll.

What You Can Still Do After 5 April 2026

2026 to 2027 Allowances to Plan Around

These values were checked against official sources on 1 July 2026.

These are planning figures, not personalised advice. Your actual tax position can depend on your income mix, Scottish tax status, pension scheme, benefits in kind, student loan plan, and whether HMRC changes your tax code.

ISA Planning

For 2026 to 2027, GOV.UK says the maximum you can save in ISAs is £20,000. The tax year runs from 6 April to 5 April.

If you missed the 2025 to 2026 deadline, you cannot usually revive that old ISA allowance. Start earlier this year instead:

• check how much of the 2026 to 2027 allowance you have already used
• decide whether cash, stocks and shares, innovative finance, or Lifetime ISA subscriptions fit your goals
• remember that a Lifetime ISA subscription is capped at £4,000 and counts towards the overall ISA limit
• keep provider confirmations for your records

ISAs are useful because interest, income, and gains inside the wrapper are not taxed in the usual way. But the right choice still depends on risk, access needs, and time horizon.

Pension Contributions

Pensions are still one of the main tax-planning tools for employees, directors, and self-employed people.

GOV.UK says the annual allowance is £60,000 this tax year. It can be lower if you have flexibly accessed pension savings or have high income. You may also be able to carry forward unused annual allowance from the previous 3 tax years.

Useful checks:

• review your 2025 to 2026 pension contributions and employer contributions
• ask pension providers for annual allowance statements if you may be close to the limit
• check whether the tapered annual allowance applies
• model salary sacrifice carefully if it affects statutory pay, benefits, mortgage affordability, or student loan deductions
• keep evidence of contribution dates and amounts

Read the salary sacrifice guide

Capital Gains Tax

The Capital Gains Tax annual exempt amount is £3,000. If you did not use the 2025 to 2026 allowance by making a disposal before 5 April 2026, that allowance has gone.

For the current tax year, the practical checks are:

• review taxable investments outside ISAs and pensions
• record acquisition costs, sale proceeds, and fees
• track losses that may offset gains
• be careful with "bed and ISA" timing and the share matching rules
• check reporting deadlines if you sell UK residential property

PayeTax is not a CGT calculator. Use HMRC guidance or a qualified adviser for disposal-specific calculations, especially for property, cryptoassets, employee shares, or business assets.

Dividends and Savings Interest

GOV.UK says the dividend allowance is £500 each year. From 6 April 2026 to 5 April 2027, dividend tax rates above the allowance are 10.75% for basic-rate taxpayers, 35.75% for higher-rate taxpayers, and 39.35% for additional-rate taxpayers.

Savings interest can be covered by the Personal Allowance, the starting rate for savings, and the Personal Savings Allowance. GOV.UK lists the Personal Savings Allowance as:

• £1,000 for basic-rate taxpayers
• £500 for higher-rate taxpayers
• £0 for additional-rate taxpayers

If you have dividends or savings outside ISAs, check whether HMRC will collect the tax through your code or whether you need Self Assessment.

Marriage Allowance

Marriage Allowance lets one spouse or civil partner transfer £1,260 of Personal Allowance to the other, reducing the recipient's tax by up to £252 in the tax year.

It is only useful where the conditions are met. Broadly, one partner must not be using all of their Personal Allowance and the other must be in the basic-rate band, or the relevant Scottish starter, basic, or intermediate bands.

The useful post-year-end point is backdating. GOV.UK currently says you can backdate claims to 6 April 2022 for eligible years.

Check Marriage Allowance

Trading, Property, and Rent a Room

If you had small side income in 2025 to 2026, check whether it needs reporting.

The trading allowance and property allowance are each £1,000. If you have both types of income, GOV.UK says you can get a £1,000 allowance for each. The rules have exceptions, so do not assume the allowance applies where income comes from an employer, connected company, partnership, or property finance-cost situation.

The Rent a Room Scheme can let you earn up to £7,500 per year tax-free from furnished accommodation in your home. The threshold is £3,750 if the income is shared.

If your gross income is above the relevant threshold, or an exception applies, check whether you need to register or file a Self Assessment return.

Self Assessment Dates for the 2025 to 2026 Return

For the tax year that ended on 5 April 2026:

If you make payments on account, also check whether 31 July 2026 applies to your 2025 to 2026 payments.

Read the Self Assessment deadline guide

PAYE Checks to Run Now

PayeTax is most useful for understanding the payroll side of the picture.

Use the calculator if you want to:

• check your take-home pay under the latest supported rates
• model pension contributions or salary sacrifice
• see National Insurance and student loan deductions
• understand whether a bonus or pay rise moves you across a threshold

Calculate your PAYE take-home pay

If HMRC has changed your tax code because of benefits, underpayments, savings interest, or estimated income, compare the code against your payslip and Personal Tax Account.

Plan the Current Year Earlier

The lesson from year-end planning is not "panic in March". It is to make the current tax year boring and controlled.

Set up a quarterly review:

1. Check salary, pension, student loan, and tax code changes.
2. Review ISA subscriptions and cash interest.
3. Track dividends and investment disposals outside tax wrappers.
4. Keep records for side income, rental income, and expenses.
5. Re-run your PAYE calculation after any pay change.

That rhythm matters more than a last-week rush.

Frequently Asked Questions

Can I still use my 2025 to 2026 ISA allowance after 5 April 2026?

No. ISA allowances apply by tax year. Once the tax year has ended, unused ISA allowance does not carry forward.

Can pension allowance carry forward?

Potentially, yes. GOV.UK says you may be able to carry forward unused annual allowance from the previous 3 tax years, subject to the rules and your earnings. This does not mean every old allowance can be used automatically.

Can I still claim Marriage Allowance for earlier years?

Possibly. GOV.UK currently says claims can be backdated to 6 April 2022 for eligible years.

What is the next Self Assessment deadline?

For the 2025 to 2026 tax year, the main online filing and payment deadline is 31 January 2027.

Where should PAYE employees start?

Check your tax code and take-home pay first, then look at any income outside payroll. PAYE usually handles salary, but it may not handle side income, gains, dividends, savings interest, or relief claims.

Official Sources Checked

• Individual Savings Accounts
• Pension annual allowance
• Capital Gains Tax allowances
• Tax on dividends
• Tax on savings interest
• Marriage Allowance
• Property and trading allowances
• Rent a Room Scheme
• Self Assessment deadlines

This article is for general information only. It is not tax, pension, investment, or financial advice. Check GOV.UK and speak to a qualified adviser if you are unsure how the rules apply to your circumstances.