Use this when you have sold shares or funds outside an ISA and want a clean first-pass estimate of the Capital Gains Tax bill for 2026/27, split across the 18% and 24% bands.
Scope note: this page is built for a standard share disposal using pooled cost, costs of purchase and sale, carried losses, and 2026/27 individual rates. Same-day and 30-day matching rules can override the simple pooled-cost method.
Use the pooled or matched cost for the shares disposed of, not the total cost of your whole account.
This should already be after Personal Allowance and any income-tax reliefs.
Estimated Capital Gains Tax due on this share disposal
£0Estimated disposal cash after sale costs and CGT: £0
Gross gain before losses and allowance£0Taxable gain after losses and annual exempt amount£0Gain taxed at 18%£0Gain taxed at 24%£0
Annual exempt amount used£0Basic-rate band left before the gain£0Net cash after CGT£0
What this means
The rate on share gains now depends on how much of the basic-rate band is still unused once your taxable income has taken its slice. The annual exempt amount should normally be used against the highest-taxed gains first.
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This calculator is for a standard listed-share or fund disposal where you already know the allowable cost of the shares sold. It is deliberately simpler than a full HMRC share matching engine.
Use it for a clean estimate when you have one disposal and you know the pooled or matched cost.
It does not attempt to work out same-day or 30-day matching for you.
ISAs, SIPs, gilts, Premium Bonds and Qualifying Corporate Bonds are outside this page because they usually do not create the same CGT charge.