Calculate your UK capital gains from your investment transaction history and generate a detailed calculation report. cgt-calc is intended for UK individual investors working from supported broker exports.

Supported sources include Charles Schwab, Freetrade, Hargreaves Lansdown, Interactive Brokers, Morgan Stanley, Sharesight, Trading 212, Vanguard, or a custom RAW format.

For supported transactions, the tool converts prices to GBP and applies the UK same-day, 30-day ("bed and breakfast"), and Section 104 holding rules. It prints a summary of disposal proceeds, allowable costs, gains, losses, dividends, and interest to the terminal and writes the full calculations to a PDF report.

cgt-calc reports the net gain from the transactions you supply and, for supported tax years, estimates the amount remaining after the annual exempt amount. It does not account for gains or losses outside those inputs, apply tax rates, work out your final tax bill, or submit a tax return. Some investment scenarios are not supported; check the relevant broker guide and the offshore funds limitations before relying on the result.

This compact 2025/26 example shows foreign-currency transactions, same-day and 30-day matching, Section 104 pooling, gains and losses, a dividend with overseas tax, and cash interest.

Install with uv (or pipx/pip) and generate a report for a tax year:

uv tool install cgt-calc
cgt-calc --year 2025 --schwab-file schwab_transactions.csv

pdflatex must be on your PATH to generate the PDF report. See Installation and Usage for details, and Brokers for how to export your transaction history.

Full documentation — installation, per-broker export guides, offshore funds (ERI), configuration, and Docker usage — lives at cgt-calc.uk.

Contributions are welcome! If you find a bug, have feature ideas, or want to add support for more brokers, please open an issue or pull request. See the development guide.

This tool is a calculation aid, not tax advice. It calculates capital gains figures from the transaction history you provide and is designed to apply the UK tax rules it supports, following the legislation and published HMRC guidance. Its authors and contributors are not acting as your tax advisers, the results may contain errors, and tax rules change.

You are responsible for providing complete data and checking the figures against your records and current HMRC guidance before using them in a tax return. For unusual or uncertain circumstances, consider consulting a suitably qualified tax adviser. The software is provided "as is", without warranty of any kind; see the MIT License.