I sat down last weekend and ran the numbers for a friend who keeps putting off investing. He makes good money but he's 35 and hasn't started. He figured he'd catch up later. I wanted to show him exactly what "later" costs.
Two investors. Both earn the same, both target a 7% annual return. But one starts at 25, the other at 35.
| Started at 25 | Started at 35 |
| $500/month from age 25 to 65 | $500/month from age 35 to 65 |
| Total invested: $240,000 | Total invested: $180,000 |
| Ends with: $1,320,000 | Ends with: $610,000 |
Ten years earlier = more than double the money. And the early starter put in less total cash. The extra decade of compounding does the heavy lifting.
Why most people underestimate this
We're bad at exponential thinking. Compound growth isn't linear. The curve gets steeper the longer it runs. This is why the 25-year-old ends up with over $700,000 more — not because they contributed more, but because their money had more time to compound on itself.
The real-world version
Most people can't start at 25. But the principle holds at any age gap. Starting at 30 vs 40? Still massive. Even $100 a month at 7% over 30 years becomes $122,000. Wait five years and that drops to $81,000.
Try it yourself with our compound interest calculator.