How do you calculate a crypto loss?

Could you elaborate on the methodology for calculating cryptocurrency losses? I'm curious to understand the steps involved and any specific formulas or metrics that are utilized. Do you start with the initial investment amount? Do you factor in trading fees, taxes, and any other relevant expenses? What about market fluctuations - how do you account for the variable prices of cryptocurrencies over time? Additionally, are there any common mistakes or pitfalls that investors should be aware of when calculating their crypto losses? I'd appreciate a detailed explanation of the process.