Utility Stack
Free finance calculator
Estimate how an initial balance, recurring contributions, return rate, compounding schedule, and inflation assumption can change future value over time.
Compound result
Enter a balance, contribution plan, and rate assumption to estimate compound growth.
Estimate only. Market returns, interest rates, taxes, fees, and contribution timing can materially change the final result.
Compound interest means growth is added back into the balance, then future growth is calculated on the larger amount. Over time, the growth can start coming from both the money you added and the growth that already accumulated.
The basic formula for a single deposit is principal times one plus the periodic rate raised to the number of compounding periods. Recurring contributions add another layer, because each contribution has a different amount of time to grow.
Enter your initial balance, contribution amount, contribution frequency, annual return assumption, compounding frequency, and time horizon. The calculator estimates the future balance, total contributions, and compound growth.
Weekly and annual contributions are normalized into a monthly equivalent so the result is easy to compare with a household budget. If you add money at the beginning of each month, check the timing box to give each monthly contribution one extra month of growth.
Small changes in the annual return rate can create large differences over long timelines. A 20-year plan is especially sensitive because every year affects the next year's balance.
Use conservative assumptions when planning essential goals. A savings account, certificate of deposit, retirement portfolio, and taxable brokerage account can all have very different risk, tax treatment, fees, and volatility.
The inflation-adjusted value estimates what the future balance might feel like in today's dollars. If inflation averages 2.5% per year, a future balance may have less purchasing power than the headline amount suggests.
This is useful for long-term planning because a large future number can look impressive while still buying less than expected. Set inflation to 0% if you only want the nominal future value.
Is this investment advice? No. It is a math estimate for planning scenarios, not a recommendation to buy or sell anything.
Why does contribution timing matter? Money added earlier has more time to earn returns. Beginning-of-month contributions usually produce a slightly higher future value than end-of-month contributions.
What should I use for the annual return rate? Use a number that matches the kind of account or investment you are modeling, and test more than one scenario instead of relying on a single optimistic rate.