Investment Growth Calculator
See what a starting balance plus steady monthly contributions becomes over time. Adjust the return, horizon, and compounding frequency to project your future portfolio. Here is what the calculator misses: real markets do not return 7% on a straight line. They run hot, then crash, then run hotter.
| Year | Contributions | Growth | Balance |
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How compound growth works
Compounding means your returns start earning returns of their own. In year one, the growth comes almost entirely from your contributions. By year twenty, most of the gains come from old earnings throwing off new earnings. That is why the year-by-year table curves up: the same return rate produces bigger dollar gains as the balance grows. Time in the market is the biggest input you actually control. The full mechanics live in our compound growth guide.
Why low-cost index funds are the usual default
Most long-term investors do not pick individual stocks. They buy low-cost index funds that hold hundreds or thousands of companies in one wrapper. The reasons are practical: broad diversification, no manager risk, and expense ratios often under 0.1%. Decades of data show most actively managed funds lose to their index after fees. Boring wins.
The difference a 1% fee makes
Fees compound too, just against you. $10,000 starting balance, $250 a month, 30 years, 7% return: about $386,000. Same setup at 6% (the same return after a 1% fee): about $311,000. That one percentage point quietly costs roughly $75,000, about a fifth of the final balance. Translation: check the expense ratio before anything else.