How the balance grows
Your starting balance earns interest for the whole period, and each monthly deposit earns interest from the moment it is added. The calculator compounds everything monthly, so interest credited in one month begins earning interest itself the next.
Because savings rates are usually modest, deposits — not interest — drive most of the growth in the early years. The interest contribution becomes more noticeable the longer the balance is left to build.
Reading the results
Future value is the projected ending balance. Total deposits is your starting balance plus every monthly deposit, and interest is the amount the account earned on top.
The line chart plots the balance rising over time, and the donut shows how much of the final total came from your own deposits versus earned interest.
Tips for savers
A few practical ways to reach a goal faster:
- Automate the monthly deposit so saving happens before you can spend it.
- Shop for a higher-yield account; even a one-point rate difference adds up over years.
- Keep the money untouched, since withdrawals reset the compounding clock.
What to keep in mind
The projection assumes a fixed rate and steady deposits. Real savings rates change, and interest is typically taxable. Inflation also erodes purchasing power, so the future balance buys less than the same amount today.
Formula
r = annualRate/100/12; n = years×12; fv = P·(1+r)ⁿ + D·(((1+r)ⁿ − 1)/r)Frequently asked questions
- Does the rate stay fixed?
- This assumes a constant annual rate. Real savings rates can change over time, so treat the result as an estimate.