Compound interest calculator
See how your money could grow.
Adjust your plan, compare contributions, and explore two possible futures in a little snowy world. Every balance is a hypothetical estimate.
Used to estimate the future total's buying power in today's money.
Small beginnings. More momentum.
Watch your money snowball.
Two possible futures. One little snowy world.
A little momentum is on its way…
Your starting point
Your plan
$1,000.00- Money put in
- $1,000.00
- Estimated growth
- $0.00
Comparison
$1,000.00- Money put in
- $1,000.00
- Estimated growth
- $0.00
Both plans have the same balance at this point.
Try a different contribution
$150.00 per month in the comparison.
Use the comparison field above for an exact amount. All other assumptions stay the same.
Snowball volume represents positive balance on the same scale for both plans. Travel along the tracks represents time, not returns. The illustration and future balances are hypothetical; real investments can lose value.
See the path
Growth over time
Each row uses the same assumptions as your estimate.
| Time | You put in | Estimated growth | Balance |
|---|---|---|---|
| Start | $1,000.00 | $0.00 | $1,000.00 |
| 1 year | $1,000.00 | $51.16 | $1,051.16 |
| 2 years | $1,000.00 | $104.94 | $1,104.94 |
| 3 years | $1,000.00 | $161.47 | $1,161.47 |
| 4 years | $1,000.00 | $220.90 | $1,220.90 |
| 5 years | $1,000.00 | $283.36 | $1,283.36 |
| 6 years | $1,000.00 | $349.02 | $1,349.02 |
| 7 years | $1,000.00 | $418.04 | $1,418.04 |
| 8 years | $1,000.00 | $490.59 | $1,490.59 |
| 9 years | $1,000.00 | $566.85 | $1,566.85 |
| 10 years | $1,000.00 | $647.01 | $1,647.01 |
The compounded rate includes the effect of compounding. All-time return is estimated growth divided by all money contributed. Doubling time uses the rate alone and ignores future contributions. Today's value discounts the final balance using a steady annual inflation rate; it does not change deposits or withdrawals. These figures are not predictions of actual investment performance.
How this estimate works
Compound interest means growth can earn growth: your balance may earn a return on both the money you put in and the return already added to it. The estimate applies the rate and timing you choose, then separates your deposits from estimated growth.
Important assumptions
This is an educational estimate in your selected currency. Changing the currency changes formatting; it does not convert money. The inflation-adjusted total discounts only the final balance using the steady annual rate you enter; it does not increase future deposits or withdrawals. The estimate does not include taxes, fees, changing rates, or market volatility. Actual investment returns can be negative, and a bank's advertised APY may differ from the nominal annual rate entered here.
About the comparison
The comparison changes only your recurring contribution. It keeps your starting amount, time, return, compounding, and timing the same so you can see the potential effect of saving more.
Formula and timing
For each compounding event, the balance is multiplied by 1 + (annual rate ÷ compounding periods per year). Contributions are added at the beginning or end of their selected period. When events happen together, a beginning-of-period contribution earns that period's return; an end-of-period contribution does not.
How the inflation adjustment works
The calculator divides the future balance by 1 plus the expected annual inflation rate, raised to the number of years in your plan. This expresses the final total in today's buying power. Inflation varies over time, so this is a planning estimate rather than a prediction.
Explore the snowball effect
Move the timeline or choose “Let it roll” to see your balance and the contribution comparison at the same point in time. The front track shows your plan; the back track shows the comparison. Snowball volume represents positive balance on a shared scale. The tracks represent time, so arriving at the end is not a savings target or a guaranteed return.
The exact balances, money contributed, growth, and withdrawals stay visible as text. A zero or negative balance leaves its track empty. The illustration uses the same projection calculations as the table, and the calculator remains available without 3D support.
Sources
- SEC Investor.gov compound interest calculator
- Consumer Financial Protection Bureau: How does compound interest work?
- FDIC: Compound interest
Sources reviewed August 26, 2026. My Handy Calc provides educational estimates, not financial, investment, or tax advice.
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