Use it or lose it before 5 April. ISA allowance, pension contributions, Capital Gains allowance, Marriage Allowance, and more. Complete tax year end checklist.
·4 min read
Don’t let valuable allowances expire unused. Here’s what to check before 5 April.
Key Dates
Important Deadlines
Date
Event
5 April
Tax year ends
6 April
New tax year begins
Allowances reset
ISA, CGT, dividend, pension annual
Can’t carry forward
Most allowances lost
Planning Timeline
When
Action
February
Review and plan
March
Take action
Early April
Final checks
5 April
Deadline
ISA Allowance (£20,000)
The Basics
Feature
Details
Annual allowance
£20,000
Carry forward
No — use it or lose it
Split between
Cash ISA, Stocks & Shares ISA, LISA
Tax benefit
All growth/interest tax-free
ISA Types
Type
2025-26 Allowance
Cash ISA
Part of £20,000
Stocks & Shares ISA
Part of £20,000
Lifetime ISA
£4,000 max (within £20,000)
Innovative Finance
Part of £20,000
Total across all
£20,000
Action Required
Situation
Action
Haven’t used any
Open ISA, deposit what you can
Partially used
Top up
Don’t have £20k
Put in what you can
Already maxed
You’re done
Quick Wins
If You Have
Do
£100+ spare
Open Cash ISA
Regular savings
Use Regular Saver ISA
Investments outside ISA
Bed and ISA (see below)
Savings goals
Lifetime ISA (if under 40)
Pension Contributions
Annual Allowance
Limit
Details
Standard
£60,000 per year
Earnings cap
Can’t exceed earnings
Carry forward
Up to 3 years unused allowance
High earners
May be tapered
Tax Relief
Tax Rate
On £1,000 Contribution
Basic (20%)
Costs you £800, worth £1,000
Higher (40%)
Costs you £600, worth £1,000
Additional (45%)
Costs you £550, worth £1,000
Action Required
Situation
Action
Employer scheme
Check if can increase contribution
Self-employed
Personal pension contribution
High earner
Use carry forward if available
Under-contributed
Consider lump sum
Carry Forward
How It Works
Details
Unused allowance
From last 3 years
Must have earned
In each year
Use current year first
Then oldest unused
Check records
What did you contribute?
Capital Gains Tax
Annual Exempt Amount
Year
Tax-Free Gains
2025-26
£3,000
Unused
Cannot carry forward
Above this
Taxed at 18%/24%
Bed and ISA
Step
Action
1
Sell investments with gains (up to £3,000 profit)
2
Gains are tax-free
3
Repurchase same investments in ISA
4
Future growth is tax-free
Watch Out
Details
Trading costs
May eat into benefit
30-day rule
Doesn’t apply to bed and ISA
Same-day rebuy
In ISA is fine
Only if gains
No point if losses
Capital Losses
| Can | Offset against gains |
| Carry forward | Unlimited years |
| Report | On Self Assessment |
| Strategy | Realise losses before year end |
Marriage Allowance
What It Is
Feature
Details
Transfer
£1,260 of Personal Allowance
From
Non-taxpayer to basic rate spouse
Worth
£252 per year
Backdate
Up to 4 years
Eligibility
Person
Requirement
Lower earner
Income under £12,570
Higher earner
Basic rate taxpayer (under £50,270)
Relationship
Married or civil partners
Action Required
Step
Action
Check eligibility
Both conditions met?
Apply
gov.uk/marriage-allowance
Claim backdate
Get up to £1,000+ lump sum
Take 5 minutes
Worth doing
Dividend Allowance
Tax-Free Dividends
Year
Allowance
2025-26
£500
Above this
Taxed (8.75%/33.75%/39.35%)
Action Required
Situation
Action
Dividends in ISA
Already tax-free
Dividends outside ISA
Consider Bed and ISA
Company director
Time dividend payments
Gift Aid Donations
How It Works
Feature
Details
Charity claims
25p for every £1 you give
Higher rate taxpayers
Can claim extra 25p back
Must donate
In the tax year
Year End Action
If You
Action
Plan to donate
Do it before 5 April
Higher rate taxpayer
Include in Self Assessment
Made donations
Keep records
Other Allowances
Personal Allowance
| Amount | £12,570 tax-free income |
| Action | Ensure salary sacrifice doesn’t waste it |
| Couples | Can both use own allowance |
| Amount | £1,000 |
| For | Self-employed/side income |
| If under | Don’t need to report |
| If over | Only profit above £1,000 taxed |
Summary: Tax Year End Checklist
Must-Do Before 5 April
Action
Done
Use ISA allowance (any amount)
☐
Review pension contributions
☐
Check Marriage Allowance
☐
Realise gains/losses if needed
☐
Make Gift Aid donations
☐
Check Eligibility
Allowance
Eligible
Using
ISA (£20,000)
☐
☐
Lifetime ISA (£4,000)
☐
☐
Pension (£60,000)
☐
☐
Marriage Allowance
☐
☐
CGT allowance (£3,000)
☐
☐
By Amount to Save
Action
Potential Tax Saving
Marriage Allowance
£252/year
Full ISA (over time)
Hundreds long-term
Pension contribution
20-45% of contribution
CGT allowance
Up to £720
Higher rate Gift Aid
25p per £1 donated
December/January
Action
Done
Review last year’s actions
☐
Check for carry forward (pension)
☐
Plan contributions
☐
February/March
Action
Done
Make pension contributions
☐
Top up ISA
☐
Bed and ISA if applicable
☐
Marriage Allowance claim
☐
Key Contacts
Resource
For
Gov.uk
All applications
HMRC
Tax queries
Pension provider
Contribution deadlines
ISA provider
Transfer times
Don’t leave money on the table. Most of these take minutes to action but can save hundreds of pounds. Even if you can only do one thing, use some of your ISA allowance — future you will appreciate the tax-free growth.