Compound Interest Calculator

Compound interest is the process where interest earned on an investment is added to the principal, and then future interest is calculated on the new larger amount. This creates a snowball effect where your money grows faster over time. Einstein reportedly called compound interest the eighth wonder of the world — and our Compound Interest Calculator on Diztool shows you exactly why. How to Use: 1. Enter your principal amount — the initial sum you are investing or depositing. 2. Enter the annual interest rate as a percentage. 3. Select the compounding frequency — daily, monthly, quarterly, or annually. 4. Enter the investment duration in years. 5. Optionally enter a regular monthly contribution if you plan to add money over time. 6. Click Calculate to see your total amount, total interest earned, and a year-by-year growth table. Compounding Frequency Explained: Daily compounding — Interest is calculated and added every day. Over a year this means 365 separate additions, giving slightly higher returns than less frequent compounding at the same annual rate. Monthly compounding — Interest is calculated and added 12 times per year. This is the most common frequency for savings accounts and fixed deposits. Quarterly compounding — Interest is added 4 times per year. Common for some bonds and investment products. Annual compounding — Interest is added once per year. The simplest form and the basis for the stated annual percentage rate in most financial products. The Compound Interest Formula: A = P(1 + r/n)^(nt) Where A is the final amount, P is the principal, r is the annual rate as a decimal, n is compounding frequency per year, and t is time in years. The Rule of 72: Divide 72 by your annual interest rate to estimate how many years it takes to double your money. At 8 percent annual return, 72 / 8 = 9 years to double.