Bitcoin US$ 81,026Ethereum US$ 2,615EUR/USD 1.146GBP/USD 1.334USD/BRL 5.14Bitcoin US$ 81,026Ethereum US$ 2,615EUR/USD 1.146GBP/USD 1.334USD/BRL 5.14
September 20, 2026Clear-headed personal finance. No hype.
PlanPenny
Investing Basics

Your Retirement Number: The 4% Rule Math, Step by Step

Find how much you need to retire with the 4% rule: subtract Social Security, multiply the gap by 25. Examples, tax tips, and when to use a lower rate.