Personally, I consider that specific kind of a tax field to contain way too many variables, even if we might concede that there are a lot of jurisdictional variations when it comes to tax treatment, there are also a lot of differences in regards to how any person might be treating his taxes including his ways to calculate his cost basis that could also vary based on tranches of coins that were being planned to be cashed out and how they are cashed out...there are also classified ways of spending coins that may have tax consequences in some kinds of spending, but might have exemptions in other circumstances.  Think about the context of gifting, in which in the USA, up to $17k per year per recipient could be exempted from taxes based on gifting, and there are other kinds of exemptions or reduction of tax consequences.

Sure there could be a general field rather than a tax specific field, the field would account for estimated expenses and it would reduce the payout amount in order to attempt to measure net pay as compared to gross pay, yet from my current thinking that kind of extra field seems to have tendencies to overly complicate the tool.  What do you think bitmover?  Do you want to add an expenses field?

One of the main reasons to use this kind of a tool is to get some kind of idea regarding how much BTC to withdraw and to even show maximum withdrawal amounts based on current BTC price conditions in relation to the 200-week moving average, and surely there could be some cases in which the actual benefits of the coins is reduced due to various transaction fees, taxes or other costs that could be applied right at the time of withdrawal, yet something like taxes might be a matter of how it is categorized within reporting categories that might be somewhat ambiguous and difficult to capture even if we were to put a general expenses field in there, and even if such an "expenses" field might be helpful, I am still leaning towards thinking that such a field adds more clutter, complication and distraction to the idea than it benefits - even though it is not totally irrational to want to include the consideration of those kinds of personalization ideas.