Capital Gains Tax Calculator (UK)
Calculate how much Capital Gains Tax you owe on the sale of shares, property, or other assets. Uses current UK CGT rates with the annual exempt amount applied automatically.
UK Capital Gains Tax Guide
CGT Rates for 2026/27
For shares and most assets: basic rate taxpayers pay 10%, higher/additional rate taxpayers pay 20%. For residential property (not your main home): basic rate 18%, higher rate 24% from October 2024. The annual CGT allowance for 2026/27 is £3,000 — only gains above this are taxed. This was cut from £12,300 in 2022/23 as part of HMRC's ongoing reduction of the allowance.
What Counts as a Gain
Your gain is sale proceeds minus original cost, minus any allowable costs. Allowable deductions include: purchase costs (stamp duty, legal fees), improvement costs (for property, not maintenance), and selling costs (estate agent fees, legal fees). For shares, you can also offset losses from other CGT assets in the same tax year.
Main Residence Relief
Your primary home (Principal Private Residence) is fully exempt from CGT. If you have two properties, only one can be your PPR at any time. Letting relief applies if you have rented out a property that was previously your main home. HMRC can investigate disposals going back several years if they suspect under-reporting.
Reducing Your CGT Bill
Use your annual exempt allowance every tax year — it cannot be carried forward. Transfer assets to a spouse before selling to use both allowances. Hold shares in an ISA where gains are fully exempt. Offset capital losses against gains in the same or future tax years. Consider the timing of the sale — selling in a year when your income is lower may reduce the rate applied.
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