Capital Gains Tax Allowance Calculator (UK)
Every UK taxpayer has an annual CGT allowance – a tax-free amount they can gain on asset sales each year. The allowance has fallen from £12,300 to just £3,000 for 2026/27.
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Many people mistakenly believe their CGT allowance carries forward if unused. It does not – each tax year's allowance is use-it-or-lose-it. Another common error is not considering your spouse's allowance, which can effectively double your household's allowance to £6,000 per year.
Understanding how much of your CGT allowance remains helps you decide whether to crystallise gains this tax year or defer sales. Enter your gains below to see how much falls within your tax-free allowance.
CGT Allowance Calculator
Combined gain from all disposals this tax year
How many assets you've sold
Allowance has reduced significantly since 2022
Your taxable income determines CGT rate
Each partner gets their own CGT allowance
The Capital Gains Tax (CGT) allowance is the amount of profit you can make from selling assets each year without paying tax. Understanding how to use this allowance effectively can significantly reduce your tax bill.
How the CGT Allowance Works
Annual Allowance
Each tax year, you get a tax-free allowance. Gains up to this amount attract no CGT.
Key Rules
- •Allowance applies to total gains across all assets
- •Cannot be carried forward to future years
- •Each person gets their own allowance
- •Losses can be offset against gains
Joint Ownership & Couples
Married Couples & Civil Partners
- ✓Each partner gets their own £3,000 allowance
- ✓Combined allowance of £6,000 for 2026/27
- ✓Transfers between spouses are CGT-free
- ✓Can split asset ownership to use both allowances
Example: Joint Property Sale
Same calculation applies to your partner's share
What Happens If You Exceed the Allowance
CGT Rates for 2026/27
Shares, Funds & Other Assets
Residential Property
Reporting Requirements
If your total gains exceed the allowance, you must report them to HMRC—even if you have losses that reduce your tax to zero. Property gains must be reported within 60 days of completion.
Making the Most of Your Allowance
Use It Each Year
Consider realising gains before April 5 to use your allowance. It doesn't carry forward.
Hold in ISAs
Gains within ISAs and pensions are completely exempt from CGT—no allowance needed.
Offset Losses
Capital losses can be offset against gains to reduce your taxable amount.
Frequently Asked Questions
Calculate CGT on Specific Assets
Use our specialised calculators for property or share disposals.
Protect Future Gains with ISAs
Learn how ISAs can shelter your investments from CGT entirely.
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