Include cryptocurrency (such as Bitcoin) mining as part of your gross income, even if you think of it as only a hobby.
If you:
- Mine your own cryptocurrency, it will be taxed as self-employment income at the fair market value when you get it and as property (a capital asset) for the sale
- Get paid to mine cryptocurrency, you have to report it as regular income like you would for any job (as an employee or self-employed, depending on your situation)