Quick answer
A future value calculator projects what a sum of money will be worth at a future date given a growth rate. $12,000 growing at 8% a year for 15 years has a future value of about $38,066 compounded annually — $39,683 with monthly compounding, the tool's default — the original sum plus about $26,000 of growth.
How the Future Value Calculator works, step by step
Enter the present amount, a periodic payment, the payment frequency, the annual growth rate and the number of years. The calculator compounds the lump sum and each payment for the time it is invested, then splits the result into growth on the lump sum and growth on the payments, so you can see which input is doing the work.
Frequency is a real input here, not a display choice. Monthly compounding of the same 8% turns $12,000 into $39,683 over 15 years, against $38,066 compounded annually — $1,617 more from crediting interest 12 times a year instead of once. Payments follow the same frequency: $500 a month at 8% grows to about $173,019 on its own over 15 years.
The annuity-type switch changes when payments are assumed to land. Ordinary payments arrive at the end of each period; annuity-due payments arrive at the start and earn one extra period of growth each. On the $500-a-month example that timing difference is worth about $1,153 over 15 years — small, but it is the difference between a contribution made on payday and one made a month later.
Treat the rate as the whole story. At 15 years, the difference between 6% and 8% on $12,000 is about $9,307 — a third more growth from two extra points. Fees work the same way in reverse: an investment earning 8% with a 1% annual fee compounds at about 7%, cutting the 15-year result from $38,066 to roughly $33,108.
Read the inflation-adjusted figure before deciding whether a plan is enough. The tool divides the nominal result by the inflation factor you enter: at 3% inflation, the $38,066 example is worth about $24,433 in today's purchasing power. Future value is the base calculation behind retirement projections and savings goals; its mirror image is present value, which discounts a future amount back to today at the same rate.
The formula
Future value = Present value × (1 + r)^t. With regular contributions: FV = PV × (1 + r)^t + PMT × [((1 + r)^t − 1) / r], where r is the periodic rate and t the number of periods. Annuity-due payments are multiplied by (1 + r).
Worked example — try it on the calculator above
Worked example: $12,000 at 8% for 15 years
FV = $12,000 × 1.08^15 = $12,000 × 3.172 = $38,066 with annual compounding. The growth of $26,066 is more than double the amount invested. With monthly compounding, the tool's default, the same inputs give $39,683. At 6% instead, the annual-compounded result is $28,759 — a reminder that the assumed rate, which no saver can guarantee, moves the answer more than most other inputs. Add $500 every single month and the 15-year total reaches about $212,702.
Frequently Asked Questions
What is the difference between future value and present value?
They are the same calculation run in opposite directions. Future value grows today's money forward at a rate; present value discounts a future amount back at the same rate. $38,066 in 15 years at 8% and $12,000 today are the same value expressed at different dates.
Should the growth rate be before or after inflation?
Either works, but be consistent. Use a nominal rate (for example 8%) to see the nominal future balance. Use a real rate (nominal minus inflation, roughly 5% if inflation is 3%) to see the answer in today's purchasing power — or use the tool's inflation input, which shows both.
How do fees change future value?
Fees reduce the effective rate. An investment earning 8% with a 1% annual fee compounds at about 7%. Over 15 years on $12,000 that cuts the future value from $38,066 to roughly $33,108 — the fee consumes about $5,000 of growth, which is why low-cost funds matter most over long horizons.
Does future value work for a single deposit only?
No. The formula extends to a series of deposits (an annuity) by compounding each deposit for the time it is invested. Most savings and retirement calculators are future-value calculations with a deposit stream added, and this tool's payment input is exactly that stream.
Estimates, not advice. This calculator provides educational estimates based on the inputs you enter and the assumptions shown on this page. It is not financial, tax or investment advice, and it cannot see your full situation. Verify important figures against official sources, and consider a qualified professional for decisions about your own money. See our Disclaimer and Methodology.