UK capital gains calculator

Calculate capital gains tax by transaction history exported from Schwab and generate PDF report with calculations. Automatically convert all prices to GBP and apply HMRC rules to calculate capital gains tax: "same day" rule, "bed and breakfast" rule, section 104 holding.

Report example

calculations_example.pdf

Setup

On Mac:

brew install --cask mactex-no-gui
pip3 install jinja2

Usage

• Change constants on the top of calc.py, e.g. tax year, allowance, filenames.
• schwab_transactions.csv: the exported transaction history from Schwab since the beginning. Or at least since you first acquired the shares, which you were holding during the tax year. You can probably convert transactions from other brokers to Schwab format.
• GBP_USD_monthly_history.csv: monthly GBP/USD prices from gov.uk.
• initial_prices.csv: stock prices in USD at the moment of vesting, split, etc.
• Run python3 calc.py

Testing

python3 calc.py > test_output.txt
diff test_output.txt sample_output.txt

If you are adding a new feature, please update sample_transactions.csv and sample_output.txt.

Disclaimer

Please be aware that I'm not a tax adviser so use this software application at your own risk.

Contribute

If you notice any bugs feel free to open an issue or send a PR.