Future Value Calculator: Lump Sum, Regular Payments and Inflation
Find what a starting amount plus regular deposits grows to at a rate you choose, with payments at the start or end of each period and the result in today's dollars
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Future Value Calculator: Lump Sum, Regular Payments and Inflation
Printed 2026-10-27 from billorganizingapp.com/income/calculators/future-value/ — an estimate for planning, not financial or tax advice.
The rate is your assumption. Investment returns vary and can be negative.
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Enter a starting amount (present value), what you add each period, the annual rate, the number of years and how often it compounds. Choose whether deposits go in at the end of each period (an ordinary annuity) or at the start (an annuity due). The calculator splits the future value into growth on the starting amount and on the deposits, and shows it in today's dollars at the inflation rate you enter. The rate is your assumption; actual returns vary and investments can lose value.
The future value formula
With i = annual rate ÷ periods per year and N = years × periods per year: FV = PV × (1 + i)^N + PMT × ((1 + i)^N − 1) ÷ i. For deposits at the start of each period, multiply the second part by (1 + i). $5,000 plus $200 a month at 6% compounded monthly for 20 years: the $5,000 grows to $16,551, the deposits to $92,408, a future value of $108,959 from $53,000 put in. Depositing at the start of each month instead gives $109,421; depositing $2,400 once at the end of each year with annual compounding gives $104,321.
Future value in today's dollars
Prices rise, so a future balance buys less than the same number of dollars today. Real value = FV ÷ (1 + inflation)^years. At 2% inflation — the Federal Reserve's longer-run goal — $108,959 in 20 years is worth about $73,326 in today's money. The Bureau of Labor Statistics' Consumer Price Index (CPI) shows what inflation has actually been; enter your own estimate.
How this future value calculator works, in plain language
Think of two piles of money. The first is what you start with: each period it earns the rate for that period, and the next period's interest is paid on the larger total. The second is your regular deposits: each one grows the same way, but for fewer periods the later it goes in. The calculator works out both piles at the end and adds them together. Then it divides by the inflation you entered, compounded over the years, to show roughly what that future amount would buy in today's prices. The rate stays the same every year, which real investments don't do — treat the answer as one possible path, not a forecast.
Future value examples
Six common saving patterns, computed with the same formula as the calculator. The first row uses the FDIC's national average savings rate (0.37%, September 2026 table published September 21, 2026); the other rates are examples to compare, not expected returns. "Today's dollars" assumes 2% inflation a year.
| Scenario | You put in | Future value | Growth | In today's dollars |
|---|---|---|---|---|
| $20,000 left in savings at the FDIC national savings rate for 5 years | $20,000 | $20,373 | $373 | $18,453 |
| $10,000 lump sum at 4% for 10 years | $10,000 | $14,908 | $4,908 | $12,230 |
| $100 a month at 5% for 30 years | $36,000 | $83,226 | $47,226 | $45,947 |
| $5,000 plus $200 a month at 6% for 20 years | $53,000 | $108,959 | $55,959 | $73,326 |
| $500 a month at 7% for 25 years | $150,000 | $405,036 | $255,036 | $246,882 |
| $2,000 at the start of each year at 6% for 40 years | $80,000 | $328,095 | $248,095 | $148,591 |
Common future value mistakes
The errors that most often make a future value estimate misleading.
- Mismatching deposits and periods. $500 a month at 7% for 25 years grows to $405,036 with monthly periods. Entered as $6,000 once a year at year end, it is $379,494 — the monthly deposits had longer to grow.
- Reading the result in future dollars as if it were today's. At 2% inflation, $83,226 in 30 years buys about what $45,947 buys now.
- Using an average return as if it arrived every year. Investment returns vary and can be negative; a smooth rate overstates how predictable the outcome is. Try a lower and a higher rate to see the range.
- Leaving out fees and taxes. A fund fee or tax on interest comes off the rate each year; subtract it from the rate you enter.
- Mixing up start-of-period and end-of-period deposits. Deposits at the start of each period (an annuity due) earn one extra period of interest each.
Rule of 72: a quick check
Dividing 72 by the annual rate estimates how many years money takes to double with compounding. The exact answer is ln 2 ÷ ln(1 + rate). The rule is close for rates between about 4% and 12%.
| Rate | Rule of 72 | Exact |
|---|---|---|
| 3% | 24.0 years | 23.4 years |
| 4% | 18.0 years | 17.7 years |
| 6% | 12.0 years | 11.9 years |
| 8% | 9.0 years | 9.0 years |
| 10% | 7.2 years | 7.3 years |
Growing payments
A lottery annuity pays 30 yearly payments that grow 5% a year; see what they are worth after tax and in today's money.
Official sources
Tax rules, limits and pay data change. Check the current figures with the primary source before acting on them.
Frequently Asked Questions
What is the future value formula?+
FV = PV × (1 + i)^N + PMT × ((1 + i)^N − 1) ÷ i, where i is the rate per period and N the number of periods. With no regular deposits it is just PV × (1 + i)^N.
What will $5,000 plus $200 a month be worth in 20 years?+
At 6% a year compounded monthly, $108,959 — about $73,326 in today's dollars at 2% inflation. A different rate gives a different answer; returns aren't fixed.
What is the difference between an ordinary annuity and an annuity due?+
An ordinary annuity pays at the end of each period; an annuity due pays at the start, so each deposit earns one more period of interest. In the example, that lifts the future value from $108,959 to $109,421.
How does inflation affect future value?+
Divide the future value by (1 + inflation)^years. At 2% for 20 years, every future dollar is worth about $0.67 today.
What is the rule of 72?+
72 ÷ annual rate ≈ years to double. At 6% that is 12 years; the exact figure is 11.9 years.
What is the future value of an annuity?+
It's what a series of equal deposits grows to: PMT × ((1 + i)^N − 1) ÷ i for deposits at the end of each period, where i is the rate per period and N the number of deposits. For deposits at the start of each period multiply by (1 + i).
What will $10,000 be worth in 10 years?+
At 4% a year compounded monthly, about $14,908, or $12,230 in today's dollars at 2% inflation. At a different rate the answer changes; enter your own above.
How much will $100 a month be worth in 30 years?+
At 5% compounded monthly, about $83,226 from $36,000 of deposits. That's about $45,947 in today's money at 2% inflation.
How do I calculate future value in Excel?+
Use =FV(rate/12, years*12, -monthly_deposit, -starting_amount, type), with type 0 for deposits at the end of each month and 1 for the start. Excel shows money you pay in as negative, which is why the deposit and starting amount carry a minus sign.
What is the difference between present value and future value?+
Future value moves money forward in time by adding interest; present value moves a future amount back to today by removing it. To find how much to start with or save each month for a goal, use the time value of money calculator linked below.
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