Compound interest,
visualized.
The most important number in personal finance is time. Plug in your initial amount, monthly contribution, expected return, and horizon. See the hockey stick. Then see what happens if you wait 5 years to start.
The question it answersHow much will my savings grow with monthly contributions and compounding?
Privacy: runs in your browser. What you enter stays on your device.
7% is a reasonable real (inflation-adjustedInflation-adjustedAdjusted for rising prices. Some amounts move with inflation, like IRS tax brackets, TIPS principal, or I-bond rates. Others are restated in today's dollars so different years can be compared: by the BLS consumer price index, $30,000 in 1985 bought about what $93,000 buys in 2026.) long-run return for a total-market equity portfolio. 10% is a nominal return benchmark. Use what matches your scenario.
Projection, not a promise. The result follows the assumptions you enter. Real results will differ, sometimes by a lot.
What this tool assumes
- Monthly compounding at the annual rate divided by 12.
- Contributions are added at the end of each month.
- Rate is assumed constant; real markets compound unevenly.
- Taxes and fees are not modeled; use the Expense RatioExpense ratioThe yearly fee a mutual fund or ETF charges, stated as a percentage of your investment and taken out of the fund's assets instead of billed to you. A 0.03% ratio costs $3 a year per $10,000 invested; a 1% ratio costs $100. Lower is better.Full definition Impact tool for fee impact.
Not financial advice. Compounds monthly at the annual rate divided by 12. Real returns will vary.
HOW THIS IS CALCULATED
This tool runs entirely in your browser: no data is sent to any server. The assumptions and default values behind the result are listed under “What this tool assumes” on this page. Verify the methodology or inspect the source code in your browser's dev tools.
Where to go from here
Calculators are educational estimates, not financial advice. Disclosures · How pages are reviewed