Compound Interest Calculator
See how your money grows over time with compound interest. Calculate future value with regular contributions.
What this calculator does
The Compound Interest Calculator estimates your result instantly from the values you enter, using standard investing & wealth formulas. See how your money grows over time with compound interest. Calculate future value with regular contributions. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate for planning rather than financial advice.
Investment Growth
Summary
About Compound Interest Calculator
The Compound Interest Calculator projects a final balance from an initial investment, monthly contributions, annual interest rate, duration, and selected compounding frequency. It separates the amount contributed from the interest earned.
The initial investment follows the selected compounding frequency. Monthly contributions are modeled as end-of-month deposits and always use a monthly ordinary-annuity calculation.
Formula & Mathematical Calculation
Initial-investment value = P(1 + R/f)f×t
Contribution value = PMT × [(1 + R/12)12t − 1] ÷ (R/12)
P is initial investment, R is annual rate as a decimal, f is the selected compounding periods per year, t is years, and PMT is the monthly contribution. At 0%, final value equals all contributions with no interest.
Calculation Example
Example: With a $10,000 initial investment, $500 contributed monthly, a 7% annual rate, 10 years, and monthly compounding, the final balance is $106,639.02. Total contributions are $70,000.00, leaving $36,639.02 in calculated interest.
Key Benefits
- Projects an initial investment and recurring monthly contributions
- Supports monthly, quarterly, semiannual, annual, and daily principal compounding
- Separates contributions from calculated interest
- Handles a 0% interest-rate scenario
How to Use this Calculator
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Enter contributions
Provide an initial investment, a monthly contribution, or both. -
Set rate and duration
Enter the annual interest rate and whole number of years. -
Choose compounding frequency
Select how often the initial investment compounds. Monthly deposits remain monthly in the calculation. -
Review growth
Compare final value, total contributions, and total interest.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Rates and contributions are assumed to stay constant for the whole period unless the form asks for them separately.
- Results use standard financial formulas and ignore fees, penalties and promotional terms that are not entered above.
- Inflation, tax changes and market volatility are not modelled unless a field for them is provided.
- Amounts are unit-agnostic: results are returned in the same currency you enter.
What it does not cover
- Compound Interest Calculator produces estimates for education and planning, not a quote, offer or professional advice.
- Real-world outcomes differ when fees, taxes, rounding rules or provider-specific terms apply.
- Local regulations and tax rules vary by country and change over time; verify current rules for your jurisdiction.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For decisions with lasting financial impact, confirm the numbers with a qualified professional.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.
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