I was actively trading cryptocurrencies a few years ago. All the fun died at tax time. Thousands of transactions across several exchanges and currencies, manual calculation of capital gains was out of the question.

At the time, I recall finding one or two tools on GH, none of which seemed suitable. There was also a 3rd party service for calculating tax which integrated with exchanges, but it didn't sit well with me for privacy reasons.

Eventually I felt I had no choice but to build a tool to calculate capital gains from an input CSV of transactions. I wanted to keep it simple, so it puts the burden on the user to download transactions from exchanges and get them in the correct format, which it then processes.

I finally submitted some very late tax returns, and the tax office was kind enough to withdraw the late interest penalty after I explained the effort involved.

https://github.com/dleber/capitalg