Tax Planning: UK Tax Year End — Key Dates and Deadlines for 2026/27

On 6 April 2027 every annual allowance resets to zero and any unused 2026/27 entitlement vanishes. Allowances do not roll over, with one pension exception covered below. The headline numbers for 2026/27:

• Personal allowance: £12,570 — frozen since 2021/22 and set to stay frozen until at least April 2028.
• ISA allowance: £20,000 across all types, including the £4,000 Lifetime ISA slice and a separate £9,000 Junior ISA.
• CGT annual exempt amount: £3,000 — down 76% from the £12,300 that applied as recently as 2022/23.
• Dividend allowance: £500.
• Pension annual allowance: £60,000, with three years of carry-forward.
• Marriage Allowance: £1,260 transferable to a spouse or civil partner.

Three changes make 2026/27 a genuinely different year to 2025/26. First, the dividend tax rise landed on 6 April 2026 — basic-rate dividends now cost 10.75% and higher-rate 35.75%. Second, CGT is now 18%/24% on every chargeable asset, shares and property alike, so the old assumption that shares were cheaper to sell is dead. Third, and biggest, the cash ISA allowance falls to £12,000 from April 2027. This is the final year of the full £20,000 cash allowance.

The freeze on the personal allowance is fiscal drag in action — the subject of our analysis on how frozen thresholds are costing UK taxpayers. As wages rise and the allowance does not, a larger slice of every pay rise falls into tax.

England, Wales and Northern Ireland keep the same income tax bands in 2026/27. Scotland's bands differ, so check them if you live north of the border.

Two traps sit inside those bands. The personal allowance tapers by £1 for every £2 of income above £100,000, so it disappears entirely at £125,140 — creating a 60% effective marginal rate in between. Salary sacrifice into a pension is the classic escape; our pensions hub walks through the maths.

National Insurance is where the stealth squeeze hides. Employee Class 1 NI is 8% between £12,570 and £50,270 and 2% above. The employer rate is 15% on everything above £5,000 — a quiet increase that never shows on a payslip but suppresses pay rises and hiring. Combined, a basic-rate earner loses 28p of every marginal pound to tax and NI, and someone in the taper zone loses 62p.

Your ISA allowance is £20,000 across all types in 2026/27 — Cash ISA, Stocks and Shares ISA, Lifetime ISA (capped at £4,000 with a 25% government bonus) and Innovative Finance ISA. Anything unused on 5 April 2027 is gone. ISAs have no carry-forward.

The timing matters more than usual this year. From 6 April 2027 the cash component drops to £12,000 for under-65s, while the total allowance stays at £20,000. That means £8,000 of annual cash capacity disappears for everyone under 65 — with no grandfathering of existing balances and no taper. We covered the full mechanics in our piece on the cash ISA cut.

The maths is blunt. A higher-rate taxpayer earning 4.6% on £20,000 of cash outside a wrapper pays 40% tax on every pound of interest above their £500 personal savings allowance — £168 on the £920 that £20,000 generates. Inside a cash ISA, it is zero, every single year. The wrapper is the asset.

Junior ISAs carry a separate £9,000 limit for under-18s, and the Lifetime ISA takes £4,000 with a £1,000 top-up if you are under 40 and buying a first home or saving for retirement. See our savings hub for the latest best-buy cash ISA rates.

The pension annual allowance is £60,000 in 2026/27 — including employer contributions. Since the lifetime allowance was abolished in April 2024 there is no cap on the total pot, and the tax-free lump sum is 25% up to £268,275. For very high earners the annual allowance tapers down to a minimum of £10,000.

A higher-rate taxpayer putting £10,000 into a pension pays an effective £6,000 after relief. In the 60% taper zone the effective cost is £4,000. That is why pension contributions are the highest-impact year-end move for anyone in those bands.

Carry-forward is the exception to use-it-or-lose-it. If you did not use your full £60,000 in 2023/24, 2024/25 or 2025/26, you can carry the unused allowance into 2026/27 — provided you were a member of a registered pension scheme in each of those years. That lets someone with a lump sum push well past £60,000 in a single year.

Contributions must reach your provider by 5 April 2027 to count for 2026/27. Aim for late March to be safe.

The CGT annual exempt amount is £3,000 in 2026/27. Since April 2025 the rates are a flat 18% for basic-rate and 24% for higher/additional-rate taxpayers — the old 10%/20% rate for shares is gone, and the residential-property premium has been removed. Everything is now taxed the same.

Dividends get their own squeeze. The allowance is £500, and from 6 April 2026 the rates rose to 10.75% (basic), 35.75% (higher) and 39.35% (additional). A £3,000 portfolio dividend now costs a basic-rate taxpayer £269 a year — up £50 on the old 8.75% rate. The wrapper is the only clean defence: inside a Stocks and Shares ISA dividends are tax-free.

Two year-end moves do most of the work here: bed-and-ISA (sell a gain up to £3,000, then repurchase inside the wrapper — the 30-day rule does not apply when you move into an ISA) and harvesting losses to offset future gains. Our guide to CGT rates and allowances covers both.

Now (September 2026): Check your tax code against your Personal Tax Account — a wrong code leaks money all year. Review how much ISA allowance you have used. If you are in the taper zone, arrange salary sacrifice before the year runs away.

31 January 2027: Online Self Assessment filing deadline for the 2025/26 tax year, plus any balancing payment — and your first payment on account for 2026/27. Missing it triggers an automatic £100 penalty.

5 April 2027: The 2026/27 tax year ends. ISA, CGT and dividend allowances expire. Pension contributions must be received by this date.

6 April 2027: The 2027/28 tax year begins — and the cash ISA allowance drops to £12,000 for under-65s.

31 July 2027: Second payment on account for 2026/27 Self Assessment.

5 October 2027: Deadline to register for Self Assessment if 2026/27 was the first year you had untaxed income.

31 January 2028: Online filing deadline for the 2026/27 return, the balancing payment, and the first payment on account for 2027/28.

Ranked by likely tax saving:

High impact:

1. Fill the ISA — the cash component is still £20,000 for one more year. A higher-rate taxpayer who leaves cash outside a wrapper gives HMRC up to 40% of the interest.
2. Make pension contributions if you pay higher-rate or taper-zone tax. Relief of 40% or 60% is the best return available with no market risk.
3. Harvest up to £3,000 of gains before 5 April 2027 — £720 saved for a higher-rate taxpayer.

Medium impact: 4. Claim Marriage Allowance — transferring £1,260 saves £252 a year, and you can backdate claims for up to four years via gov.uk. 5. Use the £500 dividend allowance — particularly relevant for company directors who control dividend timing. 6. Make Gift Aid donations — higher-rate taxpayers reclaim the gap between 40% and 20% relief.

Administrative: 7. Check your tax code — over a year, a wrong code quietly under- or over-collects. 8. Gather records now — P60s, dividend vouchers and CGT statements, so the January deadline is not a scramble.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.