The 4% rule, simply
Many planners use the 4% rule: you can safely withdraw about 4% of your fund each year in retirement. Flip it around — you need roughly 25× your annual spending saved. Spend $40,000/year? Target ~$1,000,000.
Why inflation matters
$1,000,000 in 30 years at 3% inflation buys what ~$412,000 buys today. This calculator always shows the today's-money value next to the nominal projection, so you plan with honest numbers.