UK Capital Gains Tax Calculator for Shares
Free calculation, no sign-in required
Supported broker files stay in this browser session. You can save a review draft on this device for 7 days, or sign in to save to your account, use AI imports or download reports.
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Start by choosing your broker, then add every export needed to cover your full account history.
Built-in broker imports
Choose your broker to process its supported export locally.
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Upload a CSV or Excel file from your investment platform to get started. We have built-in imports for Vanguard, Hargreaves Lansdown, Freetrade, Fidelity, Trading212, eToro, InvestEngine, Moneybox, Saxo, Interactive Brokers, Robinhood, Revolut, Webull, AJ Bell, Interactive Investor, IG, and Morgan Stanley, plus opt-in AI import for other brokers.
2026/27 calculator guide
Calculate share gains using HMRC matching rules
Upload a supported broker export to calculate gains and losses on shares, funds, ETFs and supported option transactions held outside an ISA or pension. For a 2026/27 tax estimate, FiscalFox applies the £3,000 annual exempt amount and the 18% or 24% main rates according to your taxable income.
1. Import
Choose one or more supported broker CSV or Excel exports. The calculator normalises dates, quantities, fees and GBP values.
2. Review
Choose your tax year and see your calculation summary. If a transaction needs more information, the review explains what is needed for that result.
3. Report
Inspect disposal-level matching and produce a calculation pack for the latest published SA108 filing years.
Need your transaction file? Follow the export instructions for AJ Bell, Vanguard or eToro, or find your platform in the broker guides.
What is free, and what do you pay for?
Calculate free
Upload supported broker files and see your calculation summary, including gains, losses and an estimated tax figure. You can start without signing in or entering payment details.
Report pack: £39.99 per tax year
A one-time purchase unlocks that year's detailed disposal breakdown, audit trail and PDF and CSV reports. Sign in when you are ready to buy and download. There is no subscription.
Worked example: selling part of a share holding
Suppose you hold 1,000 shares in one company, with a total Section 104 pooled cost of £10,000 including allowable purchase costs. You sell 600 shares in 2026/27 and receive £10,000 after selling fees. There are no purchases of the same shares on the sale date or in the following 30 days, so the sale is matched to the pool.
| Calculation | Amount |
|---|---|
| Sale proceeds after selling fees | £10,000 |
| Matched pool cost: 600 ÷ 1,000 × £10,000 | £6,000 |
| Gain on this sale: £10,000 − £6,000 | £4,000 |
| Pool left for the remaining 400 shares | £4,000 |
If this is your only gain for the year, you have no losses to deduct and your full £3,000 annual exempt amount is available, the taxable gain is £1,000. The tax would be £180 if all of that gain fits within your unused basic-rate band, or £240 if all of it is above the band. A gain spanning the band is taxed partly at each rate.
The allowance applies to your total gains for the tax year, not separately to each sale or broker. The calculator brings your transactions together before working out the yearly result. See the Section 104 guide for pool workings and HMRC's explanation of CGT rates for the income-band calculation.
See what your report contains
The report pack connects the tax-year summary to the calculations behind it: disposal proceeds, allowable costs, gains and losses, share-matching details and Section 104 pool workings. For published filing years, it also includes SA108 supporting figures for your Self Assessment return.
View the sample report (PDF)The sample uses fictional transactions for 2025/26 to show the report layout. Downloading your own report does not submit your tax return to HMRC.
What the calculation covers
- Same-day acquisitions before later matching rules
- Acquisitions in the 30 days after a disposal
- Section 104 pooled quantities and allowable costs
- Current-year losses found in the imported transactions
- Foreign-currency conversion where the broker export supplies or supports the required data
- A cross-broker calculation for matching securities
Important limits
FiscalFox does not currently accept pasted transaction text. Losses from earlier years are applied only when you enter them for a selected tax year, and only down to the annual exempt amount. Complex reorganisations and corporate actions may require review. A 2026/27 estimate is useful for planning, but HMRC has not yet published the 2026/27 SA108 form. This tool provides calculations and supporting evidence, not personal tax advice.
How the result can be checked
Every result should be traceable back to the source rows and matching rule used. Read the calculation methodology, inspect the synthetic sample report, or compare the product honestly on the FiscalFox vs CGTCalculator page.
Frequently asked questions
Is the capital gains tax calculator free?
You can upload supported broker files and see your calculation summary for free, without signing in. A downloadable report pack costs £39.99 for one tax year, as a one-time purchase. Sign in when you want to save to your account or buy and download a report.
What are the UK Capital Gains Tax rates for shares in 2026/27?
For disposals of shares and most other chargeable assets in 2026/27, the main CGT rates are 18% to the extent gains fall within the unused basic-rate band and 24% above it. The annual exempt amount is £3,000 for individuals.
Which share matching rules does this calculator use?
FiscalFox applies HMRC share identification in order: acquisitions on the same day, acquisitions in the following 30 days, then the Section 104 holding.
Can FiscalFox import more than one broker?
Yes. FiscalFox can combine supported files from multiple brokers before applying share matching, which matters because matching is performed across the investor’s transactions rather than separately by broker account.
Does the calculator apply losses brought forward from earlier tax years?
Yes, for one selected tax year. Enter the unused losses you reported to HMRC in earlier years under "Losses from earlier years". FiscalFox applies them after that year's own losses and only as far as needed to bring net gains down to the annual exempt amount, then shows how much was used and how much is left to carry forward.