[shostack]

Any recommendations for a free spreadsheet version or open source version that doesn't require giving my financial data to yet another 3rd party and tying it to a unique identifier via login?

[rwol]

Here's a login-less one that looks like it doesn't make any network calls with the data you enter: https://networthify.com/calculator/earlyretirement

[fjsolwmv]

http://firecalc.com is the best.