Retirement Calculator

Why I built it

This one is deliberately simple. Enter a starting balance, an annual interest rate, and the amount spent each month.

The calculator walks forward month by month, subtracting spending and adding monthly interest until the money runs out.

If the balance begins growing instead of shrinking, it reports that the entered assumptions produce effectively indefinite earnings. It is not a full retirement model. It was a direct answer to one practical question my mom wanted to explore.