Savings
Compound Interest Calculator
Project investment growth with recurring contributions and configurable compounding. Adjust the example inputs to explore how different assumptions affect the estimate.
Your scenario
Adjust the numbers
Start with the example values or enter your own assumptions.
Based on your inputs
Your estimate
Educational estimate only. Actual terms, taxes, fees, and returns may differ.
Year-by-year balance
| Year | Balance |
|---|---|
| 0 | $10,000.00 |
| 1 | $14,317.45 |
| 2 | $18,901.18 |
| 3 | $23,767.64 |
| 4 | $28,934.24 |
| 5 | $34,419.51 |
| 6 | $40,243.10 |
| 7 | $46,425.87 |
| 8 | $52,989.99 |
| 9 | $59,958.96 |
| 10 | $67,357.77 |
| 11 | $75,212.92 |
| 12 | $83,552.56 |
| 13 | $92,406.56 |
| 14 | $101,806.67 |
| 15 | $111,786.55 |
| 16 | $122,381.97 |
| 17 | $133,630.89 |
| 18 | $145,573.62 |
| 19 | $158,252.95 |
| 20 | $171,714.31 |
How to use this calculator
Enter a starting balance, monthly deposit, assumed annual nominal rate, term, compounding frequency, and whether deposits arrive at the start or end of each month.
How the calculation works
Monthly rate = (1 + annual rate ÷ compounding periods)^(compounding periods ÷ 12) − 1. The calculator applies that equivalent monthly rate and adds each monthly contribution at the selected timing.
Worked example
For a $10,000 start and $300 added monthly, changing the assumed rate or the time horizon changes both the earned growth and the total deposits. Try a 0% rate to see contributions without growth.
Assumptions and limitations
Assumes a constant nominal annual rate and regular monthly deposits. It does not model fees, taxes, inflation, variable returns, or missed deposits. Fractional-period conversion is used when the compounding frequency does not align with monthly deposits.
Frequently asked questions
Are returns guaranteed?
No. A constant rate is a scenario input, not a prediction or guarantee.
When are monthly deposits added?
Choose beginning or end of month; beginning deposits receive one additional month of modeled growth.
Sources and further reading
Learn more
- How to Calculate Compound Interest →
- Simple vs. Compound Interest: How Growth Is Calculated →
- How to Reach a Savings Goal With Monthly Deposits →
- APY vs. Interest Rate: How to Compare Savings Accounts →
- The Rule of 72: Estimate How Long Savings May Take to Double →
- How Monthly Savings Deposits Grow With Compound Interest →
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Educational tool only. It does not provide personalized financial, tax, or legal advice.