How do you calculate return on investment (ROI) for cryptocurrency?

In the realm of cryptocurrency and finance, understanding how to calculate the return on investment (ROI) is crucial for assessing the performance of a particular investment. Could you elaborate on the methodology involved in calculating ROI for cryptocurrencies? Specifically, how do you factor in the initial investment amount, the current market value of the cryptocurrency holdings, as well as any relevant transaction fees or taxes? Additionally, are there any specific tools or software that you recommend to simplify the calculation process? Your insights into this matter would be greatly appreciated.