UK Tax Year-End Checklist April 2026: ISA, Pension, CGT Deadlines

Quick answer

The UK tax year runs 6 April to 5 April. The 2025/26 tax year ends at midnight on 5 April 2026. Most personal-finance allowances reset at midnight and do not roll over. The single most valuable action you can take in the final weeks is:

1. Use your £20,000 ISA subscription.
2. Top up your pension to the £60,000 annual allowance — using carry-forward if eligible.
3. Crystallise £3,000 of capital gains to use the annual exempt amount.

Everything else on the checklist below is incremental but matters.

The full year-end checklist

1. ISA — £20,000

• Cap is per individual. A couple can shelter £40,000.
• Split however you like across Cash, Stocks & Shares, Innovative Finance and Lifetime ISA — but only one of each type can receive new money per tax year.
• LISA contributions count within the £20k cap.
• Junior ISA cap (£9,000) is separate per child and uses no parental allowance.

For most savers a Stocks & Shares ISA for long horizons (5+ years) and a Cash ISA for short-term needs is the simplest split. With base rate at recent levels, a 4% Cash ISA on £20,000 saves a higher-rate taxpayer £320/year vs an unsheltered savings account once the £500 Personal Savings Allowance is used up.

2. Pension — £60,000 annual allowance (plus carry-forward)

• £60,000 is the gross input limit including employer contributions.
• You can carry forward up to 3 years of unused allowance (so 2022/23, 2023/24, 2024/25 still available) provided you were a member of a registered pension scheme in each of those years.
• High earners with adjusted income over £260,000 face the tapered annual allowance, reducing to a £10,000 floor.
• Contributions reduce adjusted net income — useful for the £100k personal allowance taper and the High Income Child Benefit Charge.

A £10,000 pension contribution from a 40% taxpayer costs only £6,000 of net pay after relief. From an earner inside the £100k–£125,140 trap, the effective relief is 60–62%.

3. Capital Gains Tax — £3,000 annual exempt amount

• £3,000 of net gains tax-free.
• Above that: residential property 18% / 24%; other assets 18% / 24%.
• The £3,000 does not carry forward — use it or lose it.
• A "Bed & ISA" sells a holding outside an ISA and re-buys inside an ISA, using the annual exemption and sheltering future growth from CGT permanently.

Worked example: Sam has £12,000 of unrealised gain on a global equity fund held outside any wrapper. By selling £3,000-worth of gain and re-buying inside her S&S ISA, she uses the annual exemption and locks in tax-free growth forever on that portion. She can repeat over four tax years to clear the whole position.

4. Inheritance Tax annual gift exemption — £3,000

• Gift £3,000 outright to anyone, exempt immediately.
• If you didn't use last year's £3,000, you can carry it forward one year only — up to £6,000 in one go.
• Plus £250 per recipient (small gifts), wedding gifts, regular gifts out of surplus income.

More detail: UK Inheritance Tax 7-Year Rule.

5. Marriage Allowance — £252 plus 4-year backdate

If one spouse earns under £12,570 and the other is a basic-rate taxpayer:

• Worth £252/year.
• Backdate up to 4 tax years — fresh 2026/27 claim can also capture 2022/23, 2023/24, 2024/25 and 2025/26.
• Apply directly on gov.uk; do not pay a refund agent.

6. Junior ISA — £9,000 per child

• Per child, not per parent.
• Doesn't roll over.
• Anyone can pay in, but the account is set up by a parent or guardian.

7. Lifetime ISA — £4,000 with 25% bonus

• £4,000 in → HMRC adds £1,000.
• Must be opened before age 40.
• Use for first home (up to £450,000) or after age 60.
• Counts within the £20,000 ISA cap.

8. Pension salary sacrifice "spring bonus" move

If you receive a March or April bonus, ask your employer in advance whether you can sacrifice it into pension. The standard payroll cut-off is usually 2–3 weeks before payday. Sacrificing a £10,000 bonus saves 40% tax + 8% NI + 13.8% employer NI (often partly shared back) — a combined effective rate of 50%+ before the contribution even compounds.

9. Self-employed: top up pension by 5 April

The pension contribution counts towards the current tax year. If you've had a strong trading year, contributing before 5 April reduces your Self Assessment bill. Limit: 100% of relevant earnings, capped at £60,000 plus carry-forward.

10. Self Assessment — Pay Class 2 NI for the state pension record

If your self-employed profits are below the small-profits threshold, voluntary Class 2 NI of £179.40 (2025/26 estimate, see HMRC for the precise figure) preserves a full qualifying year of state pension. At a current state pension value, this is one of the highest-return uses of £180 in the UK system.

11. Charity Gift Aid

Gift Aid donations made before 5 April 2026 can be carried back to the 2024/25 tax year via your Self Assessment return. Useful for higher-rate taxpayers who want to claim the 20–25% additional relief in the current year's tax bill.

12. Review your tax code

If you've had a salary change, started a side hustle, or paid into a SIPP, your PAYE tax code may be wrong. Check the latest code on your Personal Tax Account before 6 April — a wrong code costs you in either over- or under-payment.

Order of operations — the simple version

1. Workplace pension to employer match — free money, always first.
2. ISA to fill the £20,000 if money is needed within 10 years.
3. More pension if higher- or additional-rate taxpayer.
4. CGT bed & ISA if you hold investments outside a wrapper.
5. Marriage Allowance if eligible.
6. Annual gift exemption if planning IHT.

What does NOT carry forward

• ISA, LISA, Junior ISA allowances.
• CGT annual exempt amount.
• Dividend allowance (£500).
• Personal Savings Allowance (£1,000/£500/£0).

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Related reading:

• ISA Deadline 5 April Checklist
• Pension Carry Forward Allowance 2025/26
• 5 Legal Ways to Reduce Your UK Income Tax Bill

Sources

• HMRC: Individual Savings Accounts (ISA)
• HMRC: Tax on your private pension contributions
• HMRC: Capital Gains Tax rates and annual exempt amounts
• HMRC: Marriage Allowance
• gov.uk: Self Assessment tax returns