Capital Gains Tax (CGT) is one of the most misunderstood taxes in the UK, yet it affects millions of people who sell assets such as property, shares, or valuable possessions. Whether you're selling a buy-to-let property, cashing in investments, or disposing of a business, understanding how CGT works can help you legally minimise your tax bill and avoid costly mistakes.

Key Takeaway

Capital Gains Tax is charged on the profit you make when selling or disposing of an asset that has increased in value—not on the total sale price. You only pay CGT on gains above your annual tax-free allowance.

What is Capital Gains Tax?

Capital Gains Tax is a tax on the profit (or 'gain') you make when you sell, give away, exchange, or otherwise dispose of an asset that has increased in value. The tax applies to the difference between what you originally paid for the asset and what you receive when you dispose of it.

It's important to understand that CGT is completely separate from Income Tax, although your Income Tax band does affect the rate of CGT you'll pay.

Assets Subject to CGT

CGT may apply when you dispose of:

CGT Rates for 2024/25 Tax Year

The rate of Capital Gains Tax you pay depends on two factors: your total taxable income and the type of asset you're selling. Following the Autumn Budget 2024, CGT rates have increased significantly.

Tax Band Standard Assets (from 30 Oct 2024) Residential Property Carried Interest (from April 2025)
Basic Rate Taxpayer 18% 18% 32%
Higher/Additional Rate Taxpayer 24% 24% 32%

⚠️ Recent Changes

The Autumn Budget 2024 increased CGT rates on shares and other assets from 10%/20% to 18%/24%, effective from 30 October 2024. Residential property rates remain unchanged. Business Asset Disposal Relief will increase from 10% to 14% in April 2025, then to 18% in April 2026.

Annual CGT Allowance (Annual Exempt Amount)

Every individual has an annual tax-free allowance for capital gains. You only pay CGT on gains that exceed this threshold.

Tax Year Individual Allowance Trusts Allowance
2024/25 £3,000 £1,500
2023/24 £6,000 £3,000
2022/23 £12,300 £6,150

How to Calculate Capital Gains Tax

Calculating your CGT liability involves several steps:

Step 1: Calculate Your Gain

Your gain is calculated as:

Gain = Sale Price - Original Purchase Price - Allowable Costs

Step 2: Deduct Allowable Costs

You can deduct certain costs from your gain, including:

Step 3: Apply Your Annual Allowance

Subtract your £3,000 annual allowance from your total gains.

Step 4: Determine Your Tax Rate

Add your taxable gains to your income to determine which tax band applies.

📊 Worked Example: Selling a Buy-to-Let Property

Scenario: Sarah (a higher-rate taxpayer) sells a buy-to-let flat in 2024/25.

  • ✓ Purchase price (2015): £200,000
  • ✓ Sale price: £320,000
  • ✓ Stamp Duty paid: £6,000
  • ✓ Solicitor fees (purchase): £1,500
  • ✓ Solicitor fees (sale): £2,000
  • ✓ Estate agent fees: £4,500
  • ✓ Kitchen extension (improvement): £15,000

Calculation:

Gain: £320,000 - £200,000 = £120,000

Allowable costs: £6,000 + £1,500 + £2,000 + £4,500 + £15,000 = £29,000

Taxable gain: £120,000 - £29,000 = £91,000

After annual allowance: £91,000 - £3,000 = £88,000

CGT due: £88,000 × 24% = £21,120

Assets Exempt from CGT

Not all asset disposals attract CGT. The following are exempt:

CGT Reliefs and How to Reduce Your Bill

Private Residence Relief (PRR)

Your main home is usually exempt from CGT. However, you may owe some tax if you:

Business Asset Disposal Relief (formerly Entrepreneurs' Relief)

If you're selling all or part of a qualifying business, you may pay a reduced rate on gains up to a lifetime limit of £1 million. The rate is currently 10% but will increase to 14% from April 2025 and 18% from April 2026.

Investors' Relief

A 10% CGT rate on gains from shares in unlisted trading companies, with a separate £10 million lifetime limit.

Gift Hold-Over Relief

When gifting business assets or assets into certain trusts, you can defer CGT until the recipient sells.

💡 Legitimate Ways to Reduce CGT

  1. Use your annual allowance - Consider spreading sales across tax years
  2. Transfer assets to your spouse - Doubles your annual allowance to £6,000
  3. Utilise ISAs - Transfer investments into ISAs (called 'Bed and ISA')
  4. Offset losses - Capital losses reduce taxable gains
  5. Contribute to pensions - Reduces income, potentially lowering your CGT rate
  6. Claim all allowable costs - Keep records of improvements and fees

Reporting and Paying Capital Gains Tax

When to Report

The reporting requirements depend on what you've sold:

Asset Type Reporting Deadline Payment Deadline
UK Residential Property Within 60 days of completion Within 60 days of completion
Other Assets (shares, etc.) By 31 January after the tax year By 31 January after the tax year

Final Thoughts

Capital Gains Tax can significantly affect the profit you keep when selling assets, but careful planning helps reduce the bill. Make full use of your annual exempt amount, consider transferring assets to a spouse or civil partner to use both allowances, and hold investments in tax-efficient wrappers like ISAs where possible. Because rates, allowances, and reporting deadlines change, always confirm the current rules on GOV.UK or with a tax adviser before completing a sale.