Free savings and investment tool
Estimate how your money can grow over time with compound interest, recurring deposits, flexible compounding schedules, and clear year-by-year projections.
Calculate your growthInteractive calculator
Adjust the assumptions below to model savings accounts, retirement contributions, index-fund investing, education funds, or other long-term financial goals.
See how deposits, interest, and balance can change over time.
| Year | Starting balance | Contributions | Interest earned | Ending balance |
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Compound interest is the process of earning interest on both your original money and the interest that has already been added. Over longer periods, this creates a snowball effect because each new period starts from a larger balance.
Enter your starting balance, annual return, time horizon, contribution amount, and compounding schedule. The calculator then estimates your future value, total deposits, interest earned, annual growth path, and a low-to-high range based on your chosen rate variance.
More frequent compounding can slightly increase returns because interest is added more often. The difference is usually modest over short periods but can become more noticeable over decades.
People often use compound interest calculators to plan emergency funds, retirement savings, college savings, down payments, and long-term investing goals. Results are estimates and actual investment returns can vary.
Assumptions
These assumptions keep the estimate easy to understand. Real savings and investment results can differ because of taxes, fees, inflation, market changes, product rules, and withdrawals.
Formula
For a single deposit, the common formula is A = P(1 + r/n)nt, where A is the future value, P is the principal, r is the annual rate, n is the number of compounding periods per year, and t is time in years.
Learning Center
Explore 31 beginner-friendly guides about compound interest, savings goals, recurring contributions, inflation, taxes, APY, and long-term planning.
Understand the basic idea of earning returns on previous returns.
Read guideLearn what A = P(1 + r/n)nt means in plain English.
Read guideSee why regular deposits can change long-term results.
Read guideVisit the Help Center for all 31 compound interest guides.
Questions
Compound interest can help savers and investors because returns can build on prior returns. It can also work against borrowers when debt interest compounds over time.
Use a realistic estimate based on the account or investment you are modeling. Savings accounts, bonds, and stock investments can have very different return ranges and risk levels.
No. The projection does not include taxes, inflation, investment fees, account charges, or market volatility. Consider those separately when making financial decisions.
Yes, it can provide a simple long-term estimate. For full retirement planning, also consider income needs, taxes, employer matches, inflation, withdrawal strategy, and risk tolerance.
The Rule of 72 is a quick mental shortcut for estimating how long it may take money to double. Divide 72 by the annual return percentage to get an approximate number of years.