FUTURE VALUE CALCULATOR

What does this future value calculator estimate?

Future value is the projected amount a current sum may become after earning a stated return for a specified number of periods. The core idea is the time value of money: capital available now can potentially earn a return, so the same nominal dollar amount can have different values at different dates. This calculator handles a single starting amount and can optionally include a fixed deposit or withdrawal at the beginning or end of each complete period.

The projection is mathematical, not a promise of investment performance. It assumes the entered rate stays constant, every scheduled cash change occurs as specified, and returns compound without taxes, account fees, trading costs, or interruptions. For a separate public educational tool, see the U.S. Securities and Exchange Commission's compound interest calculator.

How should each input be used?

• Present value is the amount available at time zero. It is required for a conventional lump-sum projection and must be zero or positive. A larger present value increases the future value dollar for dollar before compounding effects. Avoid entering an expected future deposit here; use the periodic change field instead.
• Number of periods is the horizon measured in the selected period length. It may include a decimal, such as 2.5 years. More periods generally increase the impact of compounding when the rate is positive and decrease the value more deeply when the rate is negative.
• Interest rate per period is the effective return applied once during each selected period. Enter 8 for 8%, not 0.08. The rate may be negative but must be greater than -100%, because a loss of 100% would reduce the balance to zero in one period and make fractional compounding undefined.
• Period length determines whether the rate and count are expressed in years or months. Switching the selector converts both values using an effective-rate equivalence, so the projected value remains essentially unchanged. A monthly rate is not simply an annual rate divided by twelve when exact compounding equivalence is required.
• Periodic change is optional. Use a positive amount for a recurring deposit and a negative amount for a recurring withdrawal. It is applied only for complete periods. Large withdrawals can drive the balance below zero; the schedule will show that outcome rather than conceal it.
• Change timing controls whether the recurring amount is applied before or after interest. A beginning-of-period deposit earns one additional period of return compared with an end-of-period deposit. The reverse is true for a withdrawal.

How does the future value formula work?

Without recurring cash changes, the standard compound future value formula is:

Here, PV is present value, r is the effective rate per period, and n is the number of periods. For example, $1,000 compounded for five yearly periods at 8% becomes $1,469.33. The $469.33 difference is compound interest, including returns earned on earlier returns.

When periodic deposits are enabled, the calculator builds the schedule period by period. End-of-period deposits are added after that period's interest. Beginning-of-period deposits are added first and therefore participate in that period's return. This iterative approach also supports negative rates, withdrawals, and a fractional final period without relying on a formula that only works for a narrow case.

Interest-rate assumptions deserve care. Market rates and investment returns change over time. The Federal Reserve publishes current U.S. benchmark and market-rate series in its H.15 Selected Interest Rates release, but a suitable planning rate depends on the account, product, risk, fees, and time horizon.

How should the results, chart, and schedule be interpreted?

Future value is the projected closing balance. Total interest equals the ending balance minus the starting value and minus net periodic changes; it can be negative when losses or withdrawal timing outweigh growth. Net periodic changes is the sum of recurring deposits and withdrawals. Net amount invested combines the starting value with those changes, while effective annual rate converts the selected periodic rate into a one-year equivalent. Growth multiple compares the ending value with the original present value and is omitted when the starting value is zero.

The line chart compares the projected balance with cumulative net invested capital. A widening positive gap represents accumulated interest; a narrowing or negative gap indicates losses. The schedule cross-checks every period: opening balance plus the period's cash change and interest reconciles to closing balance. The final row should match the headline future value exactly apart from display rounding.

Common mistakes include mixing an annual rate with monthly periods, assuming a quoted nominal rate is already an effective rate, ignoring fees and taxes, and treating a constant-return projection as a forecast. Inflation also matters because a larger future dollar amount may buy less. For goal planning, the SEC's savings goal calculator offers a complementary perspective. For retirement accounts, contribution rules and limits can affect feasible deposits; consult the IRS retirement contribution guidance and a qualified professional for account-specific questions.