Investor guide · 9 min · Reviewed 2026-09-02
Capital Gains Tax on Shares in the United Kingdom
UK capital gains tax on shares is about chargeable disposals outside sheltered wrappers, after costs and the annual exempt amount. ISAs and many pensions change the story. This guide is educational orientation for Self Assessment research - not a lodgement checklist.
What is usually in scope
Selling shares or funds in a general investment account can be a chargeable disposal. Gains inside a Stocks & Shares ISA or many pension wrappers are typically treated differently. Always separate “market P&L” from “CGT computation.”
Exempt amount and rates
Individuals often have an annual exempt amount that reduces chargeable gains; residual gains may face CGT rates that depend on income bands and asset type. Allowances and rates change with Budgets - verify the tax year you are in.
Identification and records
UK share identification rules (same-day, 30-day, section 104 pool ideas in common explanations) decide which acquisition matches a sale. Keep contract notes and corporate-action history.
Use StockWatch next
Open the UK capital-gains and accounts desks, the UK harvesting guide, and dividend-tax basics if income shares dominate your taxable account.
Simple illustration
Educational numbers only - not your return.
You sell a listed ETF in a general investment account above base cost after using part of your annual exempt amount on another gain. The residual gain may be chargeable at CGT rates for that year - subject to identification rules and your full return.
Interactive worksheet
Capital gains worksheet
Educational tool only - not tax, legal, or investment advice.
Sketch one sale, then optionally fold in other realized gains/losses for the year. This is worksheet math - not a filing estimate.
Enter proceeds and cost basis to estimate the gain or loss on one disposal.
Common mistakes
- Reporting ISA gains as if they were general-account CGT.
- Forgetting incidental costs in base cost.
- Copying U.S. long-term rate tables onto a UK return.
- Ignoring share reorganisation history.
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Guide FAQ
Short answers for discovery.
Do I pay CGT inside an ISA?
Generally gains on investments held in a Stocks & Shares ISA are not subject to CGT in the usual way - confirm current ISA rules for your case.
Are crypto disposals the same as share CGT?
Crypto can follow CGT ideas in the UK but has its own HMRC guidance. See our crypto tax guide and official pages.
Does StockWatch file Self Assessment?
No.