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- UK Tax Guide 2025/26
Complete UK Tax Guide 2025/26
Capital Gains Tax, Dividends & Self Assessment
SA108, SA100 - CGT (18%/24%), Section 104 Pooling, ISA/SIPP Tax Wrappers
KEY CHANGES FOR 2024/25 & 2025/26
CGT RATE INCREASE (October 2024)
From 30 October 2024, CGT rates increased from 10%/20% to 18%/24%. The 2024-25 tax year is a split year - use SA108 Box 51 for the rate difference on disposals after 30 October.
CGT ALLOWANCE REDUCED
The CGT annual exempt amount dropped from 6,000 (2023/24) to 3,000 (2024/25 onwards). This was previously 12,300 before 2022/23.
DIVIDEND ALLOWANCE HALVED
Dividend allowance reduced from 1,000 (2023/24) to 500 (2024/25 onwards).
Why UK Investment Taxes Feel Complicated
- - Split-year CGT rates: 2024/25 spans two rate sets with Box 51 adjustment
- - Share matching rules: Same-day, 30-day, Section 104 (not FIFO)
- - Foreign income reporting: SA106 required above £300 or when claiming tax credits
- - ISA/SIPP exclusions: Mixed accounts make tracking taxable vs tax-free hard
- - Multiple brokers: Reconciling trades, FX, and dividends across sources
What Tax-Wizard Does For You
✅ Automated calculations
- Section 104 pooling with same-day and 30-day rules
- CGT split-year handling with Box 51 adjustment
- Dividends + foreign withholding tax tracking
- ISA/SIPP exclusion and warning detection
📄 HMRC-ready reports
- SA108 (Capital Gains) box mapping
- SA100 (Dividends/Interest) mapping
- SA106 foreign income breakdowns
- Bed & Breakfast event summaries
Capital Gains Tax (SA108)
CGT Rates 2025/26
| Taxpayer Status | Rate | Income Threshold |
|---|---|---|
| Basic rate taxpayer | 18% | Up to 50,270 taxable income |
| Higher/additional rate taxpayer | 24% | Over 50,270 taxable income |
| Annual Exempt Amount | 3,000 | Tax-free allowance |
2024-25 Split Year Warning
For the 2024-25 tax year, disposals before 30 October 2024 are taxed at 10%/20%, while disposals on or after 30 October 2024 are taxed at 18%/24%. Use SA108 Box 51 to record the additional tax due.
What's Chargeable to CGT
Taxable Assets:
- Stocks and shares (outside ISA/SIPP)
- ETFs (reporting fund status)
- CFDs
- Futures contracts
- Options (traded and non-traded)
- Cryptocurrency
- Non-qualifying corporate bonds
CGT Exempt:
- UK Government Gilts
- T-Bills
- Qualifying Corporate Bonds (QCBs)
- ISA holdings
- SIPP/pension holdings
- Spread betting
SA108 Key Boxes
- Boxes 13.1-13.8: Cryptoassets (from 2024-25)
- Boxes 23-30: Listed shares and securities
- Boxes 31-38: Unlisted shares and securities
- Boxes 14-22: Other assets (incl. business assets)
- Box 51: Additional CGT due (2024-25 rate change)
Dividend Tax (SA100)
Dividend Tax Rates 2025/26
| Tax Band | Rate | Income Threshold |
|---|---|---|
| Basic rate | 8.75% | Up to 50,270 |
| Higher rate | 33.75% | 50,271 - 125,140 |
| Additional rate | 39.35% | Over 125,140 |
| Dividend Allowance | 500 | Tax-free |
Foreign Dividend Withholding
Foreign dividends may have withholding tax applied at source. You can usually claim credit for this:
- USA: 15% (with W-8BEN) - full credit available
- Ireland: 25% - up to 15% creditable
- Germany: 26.375% - up to 15% creditable
Tax-Free Investments
Tax Wrappers
| Wrapper | Annual Limit | Tax Treatment |
|---|---|---|
| ISA (Stocks & Shares) | 20,000 | No CGT, no dividend tax, no income tax |
| SIPP / Pension | 60,000* | Tax relief on contributions, tax-free growth |
| Lifetime ISA | 4,000 | 25% bonus, age 18-39 to open |
*Annual pension allowance; may be reduced for high earners
CGT-Exempt Assets
Fully Exempt:
- UK Government Gilts
- Treasury Bills (T-Bills)
- Qualifying Corporate Bonds
- Premium Bonds
- National Savings products
Spread Betting:
Spread betting profits are tax-free as they're classified as gambling. However, losses cannot offset other gains.
Cryptocurrency
Crypto Tax Treatment
HMRC treats cryptocurrency as property, not currency. The same CGT rules apply:
| Event | Tax Treatment |
|---|---|
| Selling crypto for GBP/fiat | CGT on gain |
| Swapping crypto for crypto | CGT on gain (disposal of first crypto) |
| Using crypto to buy goods/services | CGT on gain at point of spending |
| Mining income | Income tax (miscellaneous income) |
| Staking rewards | Income tax when received |
| Airdrops | Income tax if received for services |
Crypto Share Matching
The same UK share matching rules apply to crypto: Same-day → 30-day B&B → Pool. Each cryptocurrency (BTC, ETH, etc.) is tracked as a separate asset class.
Self Assessment Filing
Key Deadlines
| Tax Year | Paper Deadline | Online Deadline | Payment Due |
|---|---|---|---|
| 2024/25 | 31 Oct 2025 | 31 Jan 2026 | 31 Jan 2026 |
| 2025/26 | 31 Oct 2026 | 31 Jan 2027 | 31 Jan 2027 |
Required Forms
- SA100: Main tax return - dividends, interest income
- SA101: Additional information - other UK/foreign income not covered elsewhere
- SA108: Capital gains supplementary page - stocks, crypto, other assets
- SA106: Foreign income - if foreign income exceeds £300 or claiming foreign tax credit relief
Offshore Funds (Non-Reporting)
Non-reporting offshore funds are taxed as offshore income gains (income tax), not CGT. Use the standard share matching rules (same-day, 30-day, Section 104), and report on SA106 when required.
How Tax-Wizard Helps
Tax-Wizard generates an Excel report with values mapped to the exact SA108/SA100 boxes:
- Section 104 pooling calculations for each security
- Bed and breakfast matching applied automatically
- Separate sheets for CGT Summary, SA108 details, dividends
- Foreign tax credit calculations per country
How much is your time really worth?
Consider the value of your time and the peace of mind that comes with having a reliable and accurate tool to handle your tax reporting
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- Report with Acquisitions, Realizations, Dividends, and Interest
- Open positions report and statistics
- Transaction and dividends statistics
- Export Open Positions to Yahoo Finance