UK Tax Year Dates, Changes and Deadlines 2026/27 — What's New and WhenTax Year End Checklist UK — Don't Miss Out
Use it or lose it before 5 April. ISA allowance, pension contributions, Capital Gains allowance, Marriage Allowance, and more. Complete tax year end checklist.
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 |
Savings Allowance
| Basic rate | £1,000 interest tax-free |
| Higher rate | £500 interest tax-free |
| Additional rate | £0 interest tax-free |
| Action | Check if exceeding — use ISAs |
Trading 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 | ☐ |
| Resource | For |
|---|
| Gov.uk | All applications |
| HMRC | Tax queries |
| Pension provider | Contribution deadlines |
| ISA provider | Transfer times |
Business and Self-Employed Checklist
If you’re self-employed or run a side business, there are additional year-end actions to take:
Expenses to Review Before 5 April
| Category | Action |
|---|
| Mileage log | Ensure business miles are recorded (45p/mile up to 10,000; 25p beyond) |
| Working from home | Claim £6/week HMRC flat rate or calculate actual costs |
| Equipment purchased | Ensure qualifying assets are recorded for capital allowances |
| Business subscriptions | Paid for this tax year and expensable |
| Professional development | Training courses directly related to your work |
Self-Employed Allowances 2025/26
| Allowance | Amount | Notes |
|---|
| Trading allowance | £1,000 | If total income below this, nothing to report |
| Property allowance | £1,000 | For property income — separate from trading |
| Annual Investment Allowance | £1,000,000 | 100% relief on qualifying plant and machinery |
Payments on Account
If you pay Self Assessment tax in advance (Payments on Account), the second payment is due 31 July. If your income has fallen compared to last year, you can apply to reduce your Payments on Account to avoid cash flow strain.
Quick Reference: Key Numbers 2025/26
| Allowance / Threshold | Amount |
|---|
| ISA annual allowance | £20,000 |
| Junior ISA | £9,000 |
| Lifetime ISA | £4,000 |
| Pension annual allowance | £60,000 |
| Capital Gains Tax exempt amount | £3,000 |
| Dividend allowance | £500 |
| Personal Savings Allowance (basic rate) | £1,000 |
| Personal Savings Allowance (higher rate) | £500 |
| Personal Allowance | £12,570 |
| Trading / Property allowance | £1,000 each |
| Key Date | What Happens |
|---|
| 5 April | Tax year ends — all use-it-or-lose-it allowances expire |
| 6 April | New tax year begins |
| 31 July | Second Payment on Account for Self Assessment |
| 5 October | Deadline to register for Self Assessment (first time) |
| 31 October | Paper Self Assessment return deadline |
| 31 January | Online SA return and payment deadline |
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.
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