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. In this constant positive-return model, earlier deposits have more periods to grow. Actual investment risk and returns can change that comparison.
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. It models a constant rate; actual returns can vary from period to period.
- It ignores tax and fees. A simple rate reduction only approximates some fee arrangements. The fee comparison states how charges are applied.
- It assumes you never stop. A missed deposit reduces the amount invested and its remaining time to compound.
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, under the stated end-of-period deposit 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.
Measure a past return rather than assume a future rate
If you already know your ending balance and deposited money during the period, use the investment return calculator with contributions. The CAGR versus XIRR comparison explains why account growth can include new savings.
Reverse a future value into a present value
Use the two-way present/future value comparison to switch the known amount and inspect the equivalent balance over time.