Last updated: April 2026
The Interest Calculator lets you figure out how your savings or investments will grow over time using both compound interest and simple interest formulas. Whether you are planning a fixed deposit, comparing savings accounts, or projecting long-term investment returns, this free tool gives you a clear year-by-year breakdown of your earnings. Just enter your principal amount, annual interest rate, time period, and compounding frequency to see exactly how much your money will grow. It works great for students learning about finance, investors modeling portfolio returns, and anyone who wants to understand how compound interest works in practice. Everything runs in your browser with zero data collection.
Select either Compound Interest or Simple Interest at the top of the tool depending on which formula you want to use.
Type in the principal amount, annual interest rate, and the number of years. For compound interest, also pick your preferred compounding frequency such as monthly or annually.
Hit the Calculate button to see your total interest earned, final balance, and a complete year-by-year breakdown of how your money grows.
Use the copy button to grab a summary of your principal, total interest, and final balance for use in spreadsheets, documents, or financial plans.
Interest Calculator is the fastest way to project savings growth online. Key advantages include compound and simple interest modes, flexible compounding frequencies, and a detailed yearly breakdown table.
Simple interest is calculated only on your original principal. Compound interest is calculated on your principal plus all previously earned interest. Over time, compound interest grows your money significantly faster because you earn interest on interest. For example, $10,000 at 5% for 10 years gives you $15,000 with simple interest but $16,288.95 with annual compounding.
The more frequently interest compounds, the more you earn. Monthly compounding earns slightly more than annual compounding because interest gets added to your balance more often, which means each new calculation uses a slightly larger base. Daily compounding earns even more, though the difference between daily and monthly is usually small.
Yes. The same formulas apply to loans. Enter your loan principal, annual interest rate, and term to see how much total interest you will pay. This helps you compare different loan offers and understand the true cost of borrowing over time.
The compound interest 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 times interest compounds per year, and t is the number of years. This calculator handles all the math for you automatically.
Absolutely. All calculations happen directly in your web browser using JavaScript. No data is sent to any server, stored in any database, or shared with any third party. You can even use this tool offline once the page has loaded.