UK End of Tax Year Planning Guide (April 5 Checklist)

Why Tax Year End Matters

The 5 April deadline matters because most UK tax allowances operate on a use-it-or-lose-it basis. If you do not use your ISA allowance, pension annual allowance, CGT allowance, or dividend allowance by midnight on 5 April, they reset to zero and you cannot carry them forward (with the exception of unused pension allowances which can be carried forward up to 3 years). Last-minute planning can save thousands. For example, using your full £20,000 ISA allowance before April 5 means that amount is sheltered from tax permanently. If you miss the deadline, that £20,000 of allowance is gone forever. Over a 20-year investing career, missing one ISA allowance costs approximately £40,000–£60,000 in lost tax-free growth (assuming 5–7% annual returns). Similarly, crystallising a £3,000 capital gain before April 5 uses your CGT allowance for the year. If you have unrealised gains of £10,000, selling enough to use your £3,000 allowance resets the cost basis on those shares, potentially saving £840 in CGT (at 24% for residential property gains or 20% for other assets). Proactive vs reactive tax planning — proactive planning throughout the year is ideal, but if you have not done it, the weeks before April 5 are your last opportunity. The most effective planning actions are those that require advance notice — ISA subscriptions can be made up to midnight on April 5, but pension contributions may require payroll action if done via salary sacrifice. Start your planning at least 4–6 weeks before the deadline. The actions with the biggest potential savings are: maximising your ISA allowance, making pension contributions (especially with carry forward), and using your CGT and dividend allowances. Even if you cannot do everything on the checklist, prioritising these three areas will have the greatest impact on your long-term wealth. ISA allowance details →

ISA Allowance Checklist

The ISA allowance for 2026/27 is £20,000 across all ISA types (Cash ISA, Stocks and Shares ISA, Lifetime ISA, Innovative Finance ISA). This is a use-it-or-lose-it allowance — any unused portion cannot be carried forward. Maximise £20k ISA allowance — if you have not fully subscribed for this tax year, transfer money into your ISA before 5 April. Even if you invest in a Stocks and Shares ISA just before the deadline, you gain the tax wrapper permanently. Bed and ISA — if you have investments in a general investment account (GIA) with significant gains, you can sell them and rebuy within your ISA using the ISA allowance. This "bed and ISA" strategy moves investments into the tax wrapper, shielding future gains and income from tax. Be aware of the bed-and-breakfast rules: HMRC considers a sale and repurchase within 30 days as a single transaction for CGT purposes, but if the sale is to an ISA, this rule does not apply. You can sell in a GIA and immediately repurchase in an ISA with no waiting period. Spouse transfers — if one partner has unused ISA allowance, they can transfer cash or investments to the other partner who also has unused allowance. This is particularly useful for couples seeking to maximise their combined £40,000 ISA allowance. Transfers between spouses are exempt from CGT. Open ISA and fund before April 5 — you can open an ISA and fund it on April 5 itself. Online platforms accept payments up to midnight. However, for fixed-rate Cash ISAs, the account must be opened and funded before the deadline. For Stocks and Shares ISAs, the deadline is typically earlier on April 5 to allow for trade settlement. Check your platform's specific cutoff time. ISA transfer rules →

Pension Contributions Checklist

Pension contributions are one of the most tax-efficient ways to save, offering income tax relief at your marginal rate. The annual allowance for 2026/27 is £60,000 (or 100% of your earnings, whichever is lower). Maximise the annual allowance — if you have not used your full £60,000 allowance, consider making additional contributions before April 5. For a higher-rate taxpayer, a £10,000 pension contribution costs only £6,000 after tax relief (the pension provider claims basic rate relief automatically, and you claim higher-rate relief via your Self-Assessment). Check carry forward — you can carry forward unused annual allowance from the previous 3 tax years (2022/23, 2023/24, 2024/25). This allows you to contribute more than £60,000 in the current year if you had unused allowance in previous years. Carry forward is calculated on a FIFO basis (oldest year first). You must have been a member of a registered pension scheme in each year you carry forward from. Higher rate relief — pension contributions reduce your adjusted net income, which can also: keep you below £100,000 to avoid losing personal allowance (£1 lost per £2 over £100k), keep you below £50,000 to avoid the High Income Child Benefit Charge, and keep you below the pension annual allowance taper threshold. MPAA check — if you have flexibly accessed a defined contribution pension (taking income beyond the tax-free cash), your Money Purchase Annual Allowance (MPAA) is capped at £10,000, severely limiting further contributions. Check if the MPAA applies before making additional contributions. Employer bonus timing — if your employer offers pension matching or additional contributions via salary sacrifice, arrange for contributions to be processed before April 5. Salary sacrifice reduces your gross salary for the tax year, saving both Income Tax and National Insurance. Full pension allowance guide →

CGT and Dividend Checklist

Capital gains and dividend allowances have been significantly reduced in recent years. For 2026/27: CGT allowance: £3,000 (down from £12,300 in 2022/23). Dividend allowance: £500 (down from £2,000 in 2022/23). These are use-it-or-lose-it allowances. Use £3k CGT allowance — if you have investments in a general investment account with unrealised gains, consider selling enough to crystallise gains up to £3,000. This resets the cost basis, meaning future gains start from a higher base, potentially saving tax in future years. Even if you plan to repurchase the same investments, you can sell and rebuy immediately (no 30-day waiting period for non-ISA accounts — but beware of bed-and-breakfast rules). Bed and spouse — to use both partners' CGT allowances (£6,000 combined), transfer assets between spouses before sale. Transfers between spouses are exempt from CGT, so you can gift shares to your spouse tax-free, who can then sell and use their £3,000 allowance. Harvest losses — if you have investments with unrealised losses, consider selling them to crystallise the loss. Capital losses can be offset against capital gains in the same tax year, or carried forward indefinitely to offset future gains. Loss harvesting is particularly valuable after a market downturn. Use £500 dividend allowance — if your dividends exceed £500, consider transferring shares to your spouse if they have lower income (and therefore pay a lower dividend tax rate). Also consider using accumulation funds in ISAs to avoid dividend tax, and switching to capital growth investments rather than high-dividend investments for your GIA. Accumulation units — funds that accumulate dividends rather than distributing them still generate a tax liability on the notional dividend, but the amount is often small and may fall within the £500 allowance. Check the accumulation distribution (also known as notional distribution) reported on your annual tax certificate. Capital gains tax explained →

Other Allowances

Several other allowances should be reviewed before April 5. Marriage allowance — if you or your partner earns less than the personal allowance (£12,570), you can transfer £1,260 of allowance to the higher earner, saving up to £252. Backdating is available for 4 previous tax years — apply now even if you missed earlier years. Gift Aid — charitable donations via Gift Aid extend your basic-rate tax band, reducing your tax bill. If you are a higher-rate taxpayer, you can claim the difference between higher-rate and basic-rate relief on your Self-Assessment. Charitable donations also reduce your adjusted net income, potentially keeping you below key thresholds. EIS/VCT/SEIS — Enterprise Investment Scheme, Venture Capital Trusts, and Seed Enterprise Investment Scheme offer 30–50% income tax relief on investments. These are high-risk investments in small companies, but the tax relief is generous. Subscriptions must be completed by 5 April for the current year's relief. Pension contributions for non-earning spouse — you can contribute up to £3,600 gross (£2,880 net) to a pension for a non-earning spouse. The government adds 20% basic-rate tax relief, even if the spouse pays no tax. This is an excellent way to build retirement savings for a stay-at-home partner. Child Benefit HICBC review — if the highest earner in the household has income over £50,000, check whether additional pension contributions could reduce adjusted net income below the threshold, saving the HICBC. Savings allowance check — confirm your total savings interest for the year. If it exceeds your personal savings allowance (£1,000 basic rate, £500 higher rate), consider moving some savings to a Cash ISA or Premium Bonds before the end of the tax year. Rent-a-room allowance £7,500 — if you rent out a furnished room in your home, the first £7,500 of rent is tax-free. Ensure you have not exceeded this. Property and trading allowances £1,000 each — if you earn small amounts from property or self-employment (e.g., freelancing, selling on eBay), these allowances may cover the income, making it tax-free. Income tax bands and rates →

Action Timeline

A structured timeline helps ensure you do not miss any end-of-tax-year opportunities. December–January: review your pension carry forward position — check your annual allowance used in the previous 3 tax years and plan any additional contributions. Also review your Self-Assessment for the previous tax year (deadline 31 January). If you have a large tax bill, consider whether additional pension contributions before 31 January could reduce your liability. February: review your ISA contributions for the current year. Check how much of the £20,000 allowance you have used and plan any remaining subscriptions. Review your CGT position — calculate unrealised gains and plan any disposals to use the £3,000 allowance. Check dividend income against the £500 allowance. March: execute bed-and-ISA transactions — sell investments in your GIA and repurchase in your ISA. Make pension contributions, especially if using carry forward. Check marriage allowance and claim backdating for previous years. Review your Will and estate planning. Make any last-minute Charitable Aid donations. April 1–5: finalise any remaining ISA subscriptions. Check all contributions are made. Verify tax codes are correct. Ensure any pension salary sacrifice arrangements are processed. April 5 is the absolute deadline — most online platforms accept transactions up to midnight, but check your specific provider's cutoff times. April 6: the new tax year begins. Your allowances reset. You can start subscribing to a new ISA. Make your first contribution of the new tax year (even £1 protects the allowance for the year — you can add more later). The start of the new tax year is also a good time to review your financial plan for the coming 12 months and set savings targets. Pension annual allowance details →

FAQs

Can I carry forward unused ISA allowance?

No. The ISA allowance (£20,000 for 2026/27) is strictly use-it-or-lose-it. Any unused portion cannot be carried forward to the next tax year. However, you can transfer previous years' ISA savings between providers at any time.

What is the pension carry forward rule?

You can carry forward unused pension annual allowance from the previous 3 tax years (2022/23, 2023/24, 2024/25). This allows you to contribute more than £60,000 in the current year. Carry forward is calculated on a FIFO basis. You must have been a member of a registered pension scheme in each year you carry forward from.

Can I make ISA contributions on April 5 itself?

Yes, most providers accept ISA subscriptions up to midnight on April 5. However, for Stocks and Shares ISAs, trades may need to be placed earlier to ensure settlement occurs within the tax year. Check your provider's specific deadline. Cash ISAs can usually be funded up to midnight.

Do I need to file a Self-Assessment if I use my CGT allowance?

If you realise gains within your CGT allowance (£3,000) and your total gains and sale proceeds are below certain limits, you may not need to report them. However, if you have used any part of your CGT allowance, it is safest to report the gains on your Self-Assessment if you already file one. If you do not normally file a return, gains within the allowance do not typically trigger a filing requirement.

What if I miss the April 5 deadline?

Do not panic. The main impact is losing the current year's allowances. You can still contribute to ISAs and pensions from April 6 using the new tax year's allowances. The most important thing is to act promptly for the new tax year rather than dwelling on what was missed. Set calendar reminders for next year starting in January.