Try these example inputs in the Compound growth calculator.
These figures match this guide's worked example. They are illustrative. They stay on this device and never appear in the URL.
Compound growth is the balance you end with when a starting amount and later contributions earn a return, and that return earns a return too. It answers a forward question: if this rate holds, where does the balance land?
Key takeaways
(1 + annual)^(1 ÷ periods) − 1, so one year with no contributions lands on 1 + annual.Future value = starting balance × (1 + periodic rate) ^ periods + contribution × ((1 + periodic rate) ^ periods − 1) ÷ periodic rate
A monthly contribution uses a monthly rate. For a nominal APR that rate is the annual return divided by 12. For an effective annual return it is (1 + annual return) ^ (1/12) − 1. A yearly contribution uses the annual return once a year; in effective mode that still lands on 1 + annual after one year with no contributions. A zero return just adds the contributions to the starting balance.
Start with $10,000. Add $500 at the end of each month. The annual return is 10%, compounded monthly as a nominal APR, for 20 years.
Try the same inputs in the compound growth calculator. Leave inflation blank and the result stays in nominal dollars. Type an inflation rate and the page also restates that ending balance in today's dollars. The nominal balance does not change.
At 0% return the same $10,000 plus $500 a month for 20 years is just the money in: $130,000. Nothing compounds.
A 3% inflation rate on the $452,965 nominal ending balance is about $251,000 in today's dollars ((1.03)^20 ≈ 1.806). That restatement does not change the dollars in the account. It only asks what those future dollars buy at a steady 3% loss of purchasing power.
It separates money you put in from growth on that money, under one constant rate. That split is the useful part. A large ending balance can be mostly contributions.
Taxes, fees, and withdrawals are absent. The rate does not change from year to year, and it does not describe a path that already happened. If you already have a start value and an end value and no contributions, CAGR is the backward reading. If the cash flows are dated deposits and withdrawals, use XIRR.
A live price does not project your contributions. Type the starting balance, rate, and additions in the compound growth calculator.
For general education only. Nothing here is investment advice.
Formulas and worked examples are MarketCapLens's. See who checks the numbers.