We built these because the questions kept repeating and a paragraph was never the right answer. Each one runs on your own numbers, remembers where you got to, and is free. None of them asks for an email.
Every figure in them is dated and taken from a named source, and every one of them says plainly where it stops being reliable. They will get you to an order of magnitude and show you which variable actually matters, which is usually the useful part. They are not advice on your situation and no calculator on any website is.