Same finish line, different start
This page asks one question: if someone saves 10% of pay starting at 18, what percent would someone starting later need to save to reach the same balance at 65? Using a hypothetical 7% return after inflation and a flat salary, starting at 28 takes about 20.5%, roughly double. Starting at 35 takes about 34.9%, and at 45 about 80.3%.
Why each year early matters
Money saved at 18 has 47 years to compound; money saved at 28 has 37. At 7%, money doubles about every 10 years, so a dollar saved at 18 has had about one more doubling than a dollar saved at 28 by the time both reach 65. To make up that missing doubling, the later saver needs to put in about twice as much each year. The ladder chart shows how the steps get steeper.
Today's dollars
The 7% here is a real return, meaning after inflation, and the balance at 65 (about $1.7 million on a flat $50,000 salary) is in today's dollars. For context, S&P 500 total returns compounded about 6.8% a year after inflation from 1928 through 2025, with big swings along the way. Try 5% to see how the ladder changes.
Realistic pay paths
Most people earn less at 18 than at 35, so saving 10% at 18 means fewer dollars than 10% later. The "typical by age" path uses Bureau of Labor Statistics median weekly earnings for full-time workers by age band. With that path, the catch-up gap is gentler: starting at 28 takes about 17% instead of 20.5%. The "+2%/yr" path grows pay steadily.
What this isn't
It isn't a recommendation to save any particular percent. It's a way to see how start age and saving rate trade off under steady assumptions. Fees, taxes, employer matches and changing returns would all move the numbers.
How it's calculated
Deposits go in monthly at the monthly equivalent of the yearly rate. The required rate is the baseline rate times the ratio of the two balances: required = base × FV(from 18) ÷ FV(from your age).
Sources
- A. Damodaran, NYU Stern: historical returns on stocks, bonds and bills
- BLS: usual weekly earnings (Current Population Survey)
Last reviewed: Sep 28, 2026