Future Value Calculator
Projecting a Balance That Grows From Two Directions
Most real savings and investment accounts don't grow from a single lump sum alone — they combine an initial deposit with ongoing monthly contributions, both compounding together. This calculator handles both streams at once, computing the future value of a starting balance and the future value of a stream of monthly contributions, then adding them together for a total projected balance.
The Formula
PV is the present value (starting amount), PMT is the monthly contribution, r is the monthly rate (annual rate divided by 12), and n is the number of months. The first term grows the initial deposit; the second term grows the stream of monthly contributions as a future-value annuity.
Where This Matters
- Retirement account projections — modeling an existing 401(k) or IRA balance plus ongoing monthly contributions gives a realistic combined future value, rather than treating either stream in isolation.
- College savings planning — a 529 plan often starts with an initial deposit and continues with monthly additions; this calculator projects the combined trajectory toward a target.
- Separating growth sources — breaking out growth on the initial deposit versus growth on contributions shows which part of the strategy is doing more of the work over the chosen horizon.
Worked Example
| Component | Value |
|---|---|
| Growth on present value | $57,254.18 |
| Growth on contributions | $243,021.51 |
| Total contributed | $100,000.00 |
| Interest earned | $200,275.69 |
| Future value | $300,275.69 |
How to Use This Calculator
- Enter your present value or initial amount (optional if starting from zero).
- Enter your monthly contribution (optional if making a one-time investment).
- Enter the annual interest rate.
- Enter the number of years to project.
- Select Calculate to see the future value, broken down by growth on the initial amount versus growth on contributions.
Related Calculations
Work backward from a target with the Present Value Calculator, or model a fixed periodic contribution schedule specifically with the Dollar Cost Averaging Calculator.