Estimate how a starting balance can grow over time with compound interest and recurring contributions. This calculator supports multiple compounding frequencies so you can test savings accounts, certificates, or long-term investment plans using a consistent future value method.
What This Calculator Estimates
This calculator estimates the future value of money you already have plus the periodic contributions you expect to add. It is useful for savings plans, sinking funds, and long-range investment planning where a fixed annual rate and consistent contribution pattern are reasonable simplifying assumptions.
Formula / Method Used
The calculator combines compound growth on the starting balance with the future value of a stream of equal periodic contributions:
FV = PV x (1 + r / n)^(n x t) + PMT x [((1 + r / n)^(n x t) - 1) / (r / n)]
- PV = present value
- PMT = periodic contribution
- r = annual interest rate
- n = compounding periods per year
- t = number of years
Worked Example
Assume you start with $5,000, add $200 each month, earn 6% annually, and compound monthly for 15 years.
- Monthly rate = 6% / 12
- Total periods = 15 x 12 = 180
- The calculator compounds the $5,000 starting balance and adds the future value of the 180 monthly contributions
The final result separates your own contributions from the estimated interest earned.
What the Result Means
Future value shows the total ending balance implied by your assumptions. Total contributions shows how much of that total comes from the money you put in directly. Estimated interest earned shows the difference between the final value and your total contributions, which helps you see the effect of compounding.
Common Mistakes
- Choosing the wrong compounding frequency.
- Entering an annual contribution amount as if it were a periodic contribution.
- Assuming the rate will stay fixed for the full time horizon.
- Ignoring taxes, investment losses, or account fees.
Limitations / Disclaimer
This calculator provides informational estimates only. It assumes a fixed annual rate, regular contributions, and a stable compounding schedule. It does not include taxes, inflation, account fees, or changes in return over time. Results are estimates, not guarantees.
Last updated: May 2026
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Frequently Asked Questions
What does this future value calculator estimate?
It estimates the future value of a starting balance with periodic contributions using the interest rate, time horizon, and compounding frequency you enter.
What compounding frequency should I use?
Use the compounding schedule that matches the way the account or investment grows, such as annually, quarterly, monthly, or daily.
Does this calculator include taxes or fees?
No. This estimate focuses on compounding and contributions only. Taxes, fees, and rate changes are not included.
Are future value results guaranteed?
No. Results are estimates based on a fixed rate and contribution pattern.