How long your money lasts depends on five things: how much you start with, how much you withdraw each year, what your investments earn, how fast inflation raises your costs, and how much of your spending is covered by income that is not coming from your portfolio. As a rough anchor, a portfolio supporting a withdrawal of about 4% of its starting value, rising with inflation each year, has historically lasted around 30 years. Withdraw 8% instead and the same money may be gone in about 14 years. The calculator below turns your own numbers into a year count.