When does the UK tax year end?

The UK tax year runs from 6 April to 5 April. So the 2025/26 tax year ends at midnight on 5 April 2026. Most allowances reset on 6 April, and you lose them if unused — they don't roll over.

What should I do before tax year end UK?

Key actions: use your £20,000 ISA allowance, maximise pension contributions (up to £60,000), use Capital Gains Tax allowance (£3,000), claim tax relief you're due, make charitable donations. Check if you'll lose any allowances.

What happens to unused ISA allowance?

You lose it — ISA allowances don't carry over to the next tax year. If you don't use your £20,000 ISA allowance by 5 April, it's gone forever. However, you can withdraw and re-contribute within same tax year.

Is it too late to save tax for last year?

For ISAs, yes — must be contributed by 5 April. For pension tax relief, you have until your Self Assessment deadline (31 January) to claim relief not given at source. Some allowances can be carried back. Check specifics with an adviser.

Tax Year-End Checklist UK — Don't Miss These Deadlines | PocketWise

Tax Year-End Checklist UK — Don't Miss These Deadlines

Complete tax year-end checklist UK. ISA allowances, pension contributions, capital gains, and everything to do before 5 April to maximise tax efficiency.

By PocketWise · 23 March 2026 · 4 min read

The UK tax year ends on 5 April. Here’s everything to check before the deadline.

Key Deadlines

Use It or Lose It

Allowance	2025/26 Limit	Deadline
ISA	£20,000	5 April
Junior ISA	£9,000	5 April
Lifetime ISA	£4,000	5 April
Capital Gains Tax	£3,000	5 April
Pension annual allowance	£60,000	5 April
Personal allowance	£12,570	5 April
Dividend allowance	£500	5 April
Savings allowance	£1,000/£500	5 April

Why This Matters

If You Miss	Consequence
ISA deadline	Lose £20,000 tax-free potential
CGT allowance	Pay more tax later
Pension allowance	Miss tax relief
No rollover	These don’t carry forward

ISA Checklist

Have You Maxed Your ISA?

ISA Type	Limit	Tax Benefit
Cash ISA	Within £20,000	Tax-free interest
Stocks & Shares ISA	Within £20,000	Tax-free growth
Innovative Finance ISA	Within £20,000	Tax-free interest
Combined	£20,000 total

LISA Special Rules

Feature	Details
Lifetime ISA limit	£4,000/year
Counts towards	£20,000 total
Bonus	25% (£1,000 max)
If under 50	Consider topping up

ISA Actions

Check	Action
Current contributions	This tax year
Room remaining	£20,000 minus used
Can you top up?	Any amount helps
LISA eligibility	Under 40 to open, under 50 to contribute

Pension Checklist

Annual Allowance

Feature	2025/26
Standard allowance	£60,000
Or 100% of earnings	Whichever lower
Tax relief	At your marginal rate
Carry forward	Up to 3 years unused

Check Your Position

Review	Why
Employer contributions	Count towards limit
Your contributions	This tax year
Headroom remaining	Can you add more?
Carry forward available	From previous 3 years

Worth Extra Contribution If

Situation	Benefit
Higher rate taxpayer	40% tax relief
Approaching retirement	Boost pension
Bonus received	Sacrifice into pension
Unused carry forward	Use before it expires

Pension Carry Forward

Tax Year	If Unused
2022/23	Lost after 5 April 2026
2023/24	Carry forward to 2026/27
2024/25	Carry forward to 2027/28
Must have been member	In those years

Capital Gains Tax

CGT Allowance

Feature	2025/26
Annual exempt amount	£3,000
Per person	Not total
Doesn’t carry over	Use or lose

Bed and ISA

Strategy	How
Sell investments	Outside ISA
Use CGT allowance	On gains
Rebuy in ISA	Tax-free going forward
Rules	Wait 30 days (or use spouse)

Harvest Losses

If You Have	Action
Losing investments	Consider selling
Offset against	This year’s gains
Or carry forward	Losses to future years

For Couples

Strategy	Benefit
Transfer between spouses	Tax-free
Double allowance	£6,000 combined
Spouse sells	Instead of you

Income Tax Checklist

Personal Allowance

Feature	2025/26
Personal allowance	£12,570
Tapers from	£100,000 income
Lost completely	At £125,140
£1 lost	For every £2 over £100k

If Over £100k

Action	Benefit
Pension contribution	Reduces adjusted income
Charitable donations	Under Gift Aid
Salary sacrifice	Reduce gross income
Preserve allowance	Worth considering

Marriage Allowance

Feature	Details
Transfer	£1,260 to spouse
Must be	Non-taxpayer giving to basic-rate
Save	Up to £252/year
Backdate	Up to 4 years

Dividend & Savings

Dividend Allowance

Feature	2025/26
Tax-free dividends	£500
Above that	Taxed at dividend rates
Can’t carry over	Use or lose

Savings Allowance

Taxpayer	Tax-Free Interest
Basic rate (20%)	£1,000
Higher rate (40%)	£500
Additional rate (45%)	£0

Action Points

Check	Why
Interest received	This tax year
Dividend income	This tax year
Cash ISA room	If exceeding allowances

Charitable Giving

Gift Aid

Feature	Benefit
Basic rate	Charity claims extra 25%
Higher rate	You claim back difference
Must have paid	Enough tax to cover

Carry Back Election

Option	Details
Gift Aid donations	Can claim in previous year
Self Assessment	Carry back option
Must elect	Before SA deadline

Business & Self-Employed

Expenses

Check	Action
All expenses claimed	Review records
Receipts kept	For deductibles
Mileage logged	Business travel
Working from home	£6/week or actual

Allowances

Check	2025/26
Trading allowance	£1,000
Property allowance	£1,000
Annual Investment Allowance	£1,000,000

Your Tax Year-End Checklist

By 5 April

Priority	Action	Done?
1	Top up ISA	☐
2	Review pension contributions	☐
3	Use CGT allowance	☐
4	Check Marriage Allowance	☐
5	Make Gift Aid donations	☐
6	Use dividend allowance	☐
7	Check pension carry forward	☐

Gather for Self Assessment

Document	Purpose
P60s	Employment income
P11Ds	Benefits in kind
Bank statements	Interest received
Dividend vouchers	Dividend income
Pension statements	Contributions
Expense records	Deductions

Quick Reference

Key Numbers 2025/26

Allowance	Amount
ISA	£20,000
JISA	£9,000
LISA	£4,000
Pension	£60,000
CGT	£3,000
Dividend	£500
Savings (basic rate)	£1,000
Personal allowance	£12,570

Key Dates

Deadline	For
5 April	Tax year end
6 April	New tax year starts
31 July	2nd payment on account
5 October	Register for Self Assessment
31 October	Paper SA deadline
31 January	Online SA deadline

Summary

Priority Actions

If You Can	Do This
Have spare cash	Max ISA first
Pay higher rate tax	Consider pension
Have investments	Review CGT position
Earn over £100k	Reduce taxable income

Don’t Forget

Often Missed	Worth
Marriage Allowance	£252/year
LISA bonus	25% free money
Pension carry forward	Up to 3 years
CGT for couples	Double allowance