Using goal-seek (or equivalent) from with a function

[Jehannum]

A VBA function can't change cell values, but that's how Excel's "goal-seek" works. Therefore it would appear you can't use goal-seek from within a function.

For my application, I want to code the goal-seek part as a function, not a macro or subroutine.

Is there a built-in equivalent to goal-seek that doesn't break the functional paradigm (e.g. by using a variable instead of a cell) so that I may use it in the body of a function?

[shg]

No; goal seek changes a cell to achieve a result in another cell, and there is no other native function that works with variables in lieu of range.

[MrShorty]

Goal seek uses a basic Newton Raphson type algorithm, which is fairly easy to code from scratch. I have examples here (https://www.excelforum.com/tips-and-...ind-roots.html early posts focus on spreadsheet only implementations, the last past includes examples of a VBA implementation). See if that helps.