See how much your money would grow if you invested monthly instead of spending. S&P 500, bonds, and custom rates supported.
Shows what an expense would be worth if invested instead. Any purchase has an opportunity cost — the compound growth of investing that money over time.
Compound interest is often called the eighth wonder of the world. This calculator reveals the true opportunity cost of spending — the wealth you're forgoing every time you choose consumption over investment. The results are often staggering.
When you invest, you earn returns not just on your principal but on your accumulated returns. $100/month at 10% annual return doesn't grow linearly — it grows exponentially. After 10 years: $20,655. After 20 years: $76,570. After 30 years: $226,049. The longer the timeline, the more dramatic the compounding effect.
You don't need a large sum to start. The power of compound interest means that time matters more than amount. $50/month started at age 25 beats $200/month started at age 45, given the same total contribution amount. Every month you delay is a month of compounding lost forever.