Future Value Calculator
Calculate what a current amount could become in the future. Add optional monthly contributions when you want a more realistic savings or investing projection.
Future value vs compound interest
Future value is the ending amount. Compound interest is the growth mechanism that gets you there. This page is intentionally focused on the final value intent, while the main compound interest calculator gives a fuller table.
Common use cases
- Estimate what an existing balance may become.
- Compare different return assumptions.
- See how monthly deposits change the ending balance.
The two halves of a future value
Future value with contributions is two calculations added together, and separating them explains where the money actually comes from. Using this page's opening values — $5,000 today, $100 a month, 6% for fifteen years, compounded monthly:
| Component | Formula | Contributes | Grows to |
|---|---|---|---|
| The starting $5,000 | P × (1 + r/n)nt | $5,000 | $12,270 |
| The $100 monthly deposits | PMT × [((1 + r/n)nt − 1) / (r/n)] | $18,000 | $29,082 |
| Total | — | $23,000 | $41,352 |
The two components are computed independently and verified against the period-by-period simulation.
The lump sum multiplies by about 2.45 because every dollar of it is invested for the full fifteen years. The contributions multiply by only about 1.62, because the average deposit has been invested for roughly half that time. Both are compounding at the same rate; they simply are not compounding for the same duration.
A dollar you have today is worth more than a dollar you will contribute later — measurably more. That is the argument for investing a windfall rather than drip-feeding it, and equally the argument for starting the monthly habit as early as possible: every month of delay moves a deposit into the shorter-duration bucket.
What future value does not tell you
- It is nominal. $41,352 in fifteen years buys less than $41,352 today. At 2.5% inflation the real value is around $28,552.
- It assumes an unbroken rate. Fifteen consecutive years of exactly 6% has never happened in any real market. The average may hold; the path will not.
- It ignores tax and fees. Subtract an annual charge from the rate before calculating to approximate the drag.
- It assumes you never stop. Interrupted contributions are the most common reason real outcomes fall short of projections, and they cost most when they happen early.
For the reverse question — what a future amount is worth today — use the present value calculator. To see the same projection in inflation-adjusted terms, retirement in today's dollars does the conversion.
Questions about future value
What is the future value formula?
For a single amount, FV = P × (1 + r/n)nt. For regular deposits, FV = PMT × [((1 + r/n)nt − 1) / (r/n)]. When you have both, calculate each and add them.
Why is my future value lower than another calculator's?
Most often because the other tool credits a full period of growth to deposits made during that period. This page compounds each deposit from the point it arrives, which is the conservative and more realistic convention.
Does future value account for inflation?
Not on its own. The output is in future dollars. Divide by (1 + inflation)years to convert to today's purchasing power, or use a real rate of return as the input instead.
Can I use future value for irregular contributions?
The annuity formula assumes equal, evenly spaced deposits. For irregular amounts, calculate each deposit separately with the single-amount formula and sum the results — tedious by hand, exact in a spreadsheet.
Deposit schedule
The monthly budget is grouped into equal deposits per selected compounding period. Choose monthly compounding for a monthly deposit schedule. A final partial period earns growth but receives no deposit. See the exact model and verification method.