Explore how a starting balance and regular monthly contributions could grow over time. Compare hypothetical returns, account for annual fees and inflation, and estimate the monthly amount needed to reach a future dollar goal.
Build your investment scenario
All amounts are in U.S. dollars. The default figures are examples, not recommended returns.
Your estimated results
Compare return scenarios
Lower and higher cases vary the annual return by 2 percentage points. They are illustrations, not probabilities or best/worst outcomes.
| Scenario | Gross return | Final balance |
|---|
Year-by-year projection
| Year | Total contributed | Balance | Growth / loss | Today’s dollars |
|---|
How to read the results
Final balance combines your starting investment, monthly deposits and modeled growth. Total contributed is the money you put in. Growth or loss is the difference between these amounts. A negative number means the hypothetical investment lost value.
Today’s dollars discount the future balance using your inflation assumption. This helps show purchasing power rather than just the dollar amount on a future statement. The goal input is a future dollar amount, not an inflation-adjusted target.
Calculation assumptions
The lower scenario is capped where necessary to keep the net annual return above −100%.
- The gross annual return is treated as an effective annual rate. An approximate net rate is obtained by subtracting the annual fee in percentage points, then converting it to an equivalent monthly rate.
- Monthly contributions stay constant and arrive at the beginning or end of each month, as selected. Growth compounds monthly.
- The monthly contribution needed for your goal assumes the same starting balance, return, fees, timing and number of years.
- Annual fees are simplified. Real account fees, market movements and actual investment timing can produce different results.
- The projection excludes taxes, withdrawals, contribution limits, trading costs and changing inflation. It does not model volatility or guarantee any outcome.
- Dollar results are rounded for display; calculations use unrounded values.
Example: consistency matters
Try a starting balance of $10,000 and $250 monthly for 20 years. Then set the return to 0% and the fee to 0%. The final balance should be $70,000, consisting entirely of contributions. Compare it with a hypothetical positive return to see the effect of compounding.
Frequently asked questions
Is the assumed return guaranteed?
No. Markets can fall, and returns vary from year to year. Use several assumptions instead of treating one projection as a promise.
Why does contribution timing change the result?
A beginning-of-month deposit receives one additional month of modeled growth compared with an end-of-month deposit.
Does this calculate tax on investment gains?
No. Tax treatment depends on your account, holdings and circumstances. This tool estimates growth before taxes.
Are my inputs stored?
This calculator processes your entries in your browser. Its calculation code does not send or store your inputs.
Plan the rest of your finances
Before setting a long-term contribution, review your emergency savings target and estimate your take-home pay. Explore investing guides for more context.
For an additional educational reference, see the U.S. Securities and Exchange Commission’s Investor.gov compound interest calculator.
Educational estimate: This tool provides hypothetical projections, not personalized investment or tax advice.