The 2025/26 UK tax year ends on 5 April 2026, and several valuable allowances and reliefs expire with it — gone forever if you don't use them in time. Whether you're a basic rate taxpayer wanting to maximise your ISA, a higher earner looking to reduce your tax bill through pension contributions, or someone with investments who should be thinking about capital gains, this action plan covers everything you need to do before the deadline. Track your financial goals and progress with the SYM app so nothing slips through the cracks.
ISA Contributions: Use It or Lose It
- •Cash ISA: Even a partial contribution is better than none. If you have savings in taxable accounts, transfer what you can into a Cash ISA before 5 April
- •Stocks and Shares ISA: If you're investing for the long term, getting money into an ISA before the deadline matters more than timing the market perfectly. You can hold cash within an S&S ISA and invest it later
- •Lifetime ISA: The £4,000 annual limit sits within your £20,000 ISA allowance. If you haven't contributed the full £4,000, do so by 5 April to receive the maximum £1,000 government bonus
- •Junior ISA: Up to £9,000 per child per tax year. Contributions from parents, grandparents, and family all count toward this single limit
- •Innovative Finance ISA: If you use peer-to-peer lending, ensure any planned contributions are made before the deadline
- •Flexible ISAs: Some ISAs allow you to withdraw and replace money within the same tax year without losing the allowance. Check whether your ISA offers this feature
Pension Contributions and Tax Relief
- •Check your total contributions this tax year: Including employer contributions, salary sacrifice, and any personal contributions
- •Higher and additional rate taxpayers: Pension contributions are one of the most effective ways to reduce your tax bill. A £10,000 gross contribution costs a 40% taxpayer just £6,000 after tax relief
- •Carry forward: If you didn't use your full £60,000 allowance in 2022/23, 2023/24, or 2024/25, you can carry the unused amounts forward. This is particularly valuable if you've had a high-income year
- •Salary sacrifice: If your employer offers this, pension contributions via salary sacrifice also save National Insurance — an additional saving of up to 13.8% for the employer and 8% for you
- •Tapered annual allowance: If your adjusted income exceeds £260,000, your annual allowance is reduced by £1 for every £2 above this threshold, down to a minimum of £10,000
- •Lifetime allowance: The lifetime allowance was abolished from 6 April 2024, but a new limit on tax-free lump sums (£268,275) remains. Factor this into your planning if you have large pension pots
Capital Gains Tax: Using Your Annual Exempt Amount
- •Bed and ISA: Sell investments outside an ISA to realise gains up to your £3,000 allowance, then immediately repurchase the same investments within your ISA. This resets the base cost and shelters future growth
- •Transfers between spouses: Transfers between married couples and civil partners are CGT-free. If one partner has unused annual exempt amount, transferring assets before selling can double the tax-free amount to £6,000
- •Offset gains with losses: If you hold investments showing a loss, selling them crystallises the loss which can be offset against gains in the same or future tax years
- •Reporting deadlines: Gains on UK residential property must be reported and paid within 60 days of completion. Other gains are reported on your Self Assessment return
- •Review your portfolio: If you haven't reviewed investment performance recently, now is the time. Rebalancing before the tax year end can achieve both tax efficiency and better asset allocation
Other Tax Reliefs and Allowances to Claim
- •Marriage Allowance: Worth up to £252 per year if one partner earns under £12,570 and the other is a basic rate taxpayer. You can backdate claims for up to 4 tax years, potentially claiming £1,000+
- •Dividend allowance: Now just £500 per year. If you receive dividends outside an ISA, plan accordingly to minimise tax
- •Trading and property allowances: Each provides a £1,000 tax-free allowance for casual self-employment income and property income respectively
- •Gift Aid: If you've made charitable donations this tax year and are a higher or additional rate taxpayer, claim the extra relief on your Self Assessment return
- •Work from home allowance: If you're required to work from home (not just choosing to), you can claim £6 per week (£312 per year) tax relief via HMRC's online portal — no receipts needed
- •Professional subscriptions: Fees paid to HMRC-approved professional bodies can be claimed as a tax deduction. Check the approved list on GOV.UK
Your Tax Year End Checklist
- •Maximise ISA contributions (Cash ISA, S&S ISA, LISA, Junior ISA) — deadline: 5 April
- •Review and top up pension contributions — check carry forward from previous 3 years
- •Use your £3,000 CGT annual exempt amount — consider bed-and-ISA strategy
- •Claim Marriage Allowance if eligible (backdate up to 4 years)
- •Check your tax code on your Personal Tax Account
- •Claim work from home tax relief if applicable
- •Review direct debits and cancel unused subscriptions
- •Ensure you're on the electoral roll at your current address
- •Gather records for Self Assessment if you have untaxed income
- •Make any planned charitable donations before 5 April for this year's Gift Aid relief
FAQ
When exactly does the 2025/26 tax year end?+
The tax year runs from 6 April 2025 to 5 April 2026. All allowances and reliefs for this tax year must be used by 11:59pm on 5 April 2026. Don't leave things to the last minute — ISA providers and pension companies may need processing time.
Can I open an ISA after 5 April and backdate it to this tax year?+
No. ISA contributions must be physically received by your provider before the end of the tax year. Allow at least 2–3 working days for bank transfers to clear if you're contributing close to the deadline.
I haven't used my ISA allowance at all this year. Is it too late?+
It's not too late if you act before 5 April. Even contributing a partial amount is worthwhile. Many providers let you open and fund an ISA online in minutes. Getting money in before the deadline — even if you haven't chosen specific investments yet — secures the allowance.
What's the most tax-efficient thing I can do with a spare £1,000 before 5 April?+
For most people, putting it into an ISA (Cash or Stocks & Shares) is the best move as it shelters future growth from tax permanently. If you're a higher rate taxpayer, a pension contribution gives immediate 40% tax relief but the money is locked until age 57. If you're 18–39 and saving for a first home, a Lifetime ISA contribution gets you a 25% bonus.
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