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Enter values and click Calculate// find final amount with compound interest in one click
Calculate compound interest instantly. Find final amount, total interest earned, and year-by-year growth with principal, rate, frequency, and duration.
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Enter values and click CalculateType the initial investment or deposit amount in the Principal field.
Enter the annual interest rate (%) and the number of years for the investment.
Select how often interest compounds (monthly is common), then click Calculate to see the full breakdown.
This Compound Interest Calculator computes how an initial amount grows over time when interest is earned on both the principal and the previously accumulated interest. Just enter your values and get an instant result — no signup required.
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest (which only earns on the principal), compound interest causes your balance to grow exponentially over time — often called "interest on interest."
Compounding frequency is how often interest is calculated and added to your balance per year. Common options are daily (365×), monthly (12×), quarterly (4×), and annually (1×). More frequent compounding means slightly more interest earned over time.
The standard formula is A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual interest rate (as a decimal), n is the number of compounding periods per year, and t is the time in years.
The Effective Annual Rate accounts for compounding within the year and shows the true annual return. For example, a 5% rate compounded monthly yields an EAR of about 5.116%. This tool calculates and displays EAR automatically.
This calculator focuses on a single lump-sum principal. It does not currently include monthly contributions (PMT). For scenarios with regular deposits, you would need a future value of annuity formula — a feature we may add in a future update.
Yes — the calculation uses the standard compound interest formula with floating-point arithmetic, rounded to 2 decimal places for display. Results are suitable for planning and education. For precise financial decisions, consult a licensed financial advisor.
A compound interest calculator is an online tool that lets you quickly determine how much an initial sum of money will grow over a specified period at a given interest rate, accounting for the compounding effect. Instead of manually applying the compound interest formula, you simply enter your principal amount, annual interest rate, time horizon, and compounding frequency — and the calculator does all the work instantly.
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With simple interest, you earn a fixed percentage of the original principal each period. If you deposit $10,000 at 5% simple interest for 10 years, you earn $500/year — a total of $5,000 in interest, giving you $15,000 at the end.
With compound interest, each period's interest is added to the principal, so the next period earns interest on a larger amount. The same $10,000 at 5% compounded monthly for 10 years grows to approximately $16,470 — over $1,470 more than simple interest alone. This difference becomes dramatically larger over longer time horizons, which is the core principle behind long-term investing.
The standard formula is:
A = P × (1 + r/n)^(n × t)For example: $10,000 at 5% compounded monthly for 10 years → A = 10000 × (1 + 0.05/12)^(12×10) ≈ $16,470.09
The more frequently interest compounds, the faster your money grows. Here is a comparison for $10,000 at 5% annual rate over 10 years:
While the differences seem small at first, they become more significant with higher principal amounts or longer time periods. Daily compounding is offered by many high-yield savings accounts and money market funds.
The Effective Annual Rate (EAR), also called the Annual Equivalent Rate (AER), is the actual return per year after accounting for compounding within the year. It is calculated as:
EAR = (1 + r/n)^n - 1For example, a 5% nominal rate compounded monthly gives an EAR of about 5.116%. This metric is useful for comparing financial products that use different compounding frequencies on an apples-to-apples basis.
Compound interest is fundamental to many areas of personal finance and investing:
To get the most out of compounding:
Using the JLV DevTools Compound Interest Calculator is simple: enter your principal (the starting amount), your annual interest rate as a percentage, the duration in years, and select how often interest compounds. You can also choose your currency symbol for display purposes. Click Calculate to instantly see the final balance, total interest earned, effective annual rate, a visual bar showing principal vs. interest, and a year-by-year breakdown table. No account, no download, and no server upload required — all calculations happen in your browser.