Investment Calculator

How Investment Growth is Calculated

This calculator uses compound interest formulas for both the initial lump sum and monthly contributions. The initial investment grows as FV = P(1 + r)^n, while monthly contributions use the future value of an annuity formula.

Example

Investing $5,000 upfront plus $200/month for 20 years at 7% annual return yields approximately $107,000 — on total contributions of just $53,000. The market does the rest.

Tips for Maximizing Returns

• Even small monthly contributions make an enormous difference over long time horizons.
• Starting 10 years earlier can more than double your final balance.
• Tax-advantaged accounts (401k, IRA, Roth) can significantly boost real returns.
• Keep fees low — even a 1% annual fee can cost tens of thousands over decades.