Interest Calculator
Calculate simple and compound interest. Select compounding frequencies (daily, monthly, quarterly, yearly) and view detailed breakdown reports.
Maturity Amount
Principal Amount
$0
Total Interest Earned
$0
The Magic of Compound Interest
Interest calculators help savers and investors project how compounding growth elevates wealth over time. While simple interest pays linear returns, compound interest adds generated interest to the principal base periodically, creating compounding cycles.
Compounding Frequency Explained
When interest is compounded monthly or quarterly, the accumulated earnings grow faster than they would under yearly compounding. This rate difference is called the Annual Percentage Yield (APY) or Effective Annual Rate (EAR).
Frequently Asked Questions
Simple interest is calculated solely on the principal (the initial amount invested or borrowed). Compound interest is calculated on the principal plus any accumulated interest from previous periods, meaning you earn interest on your interest.
The more frequently interest compounds (e.g., daily vs. annually), the faster your money grows. Daily compounding yields slightly higher interest returns than monthly or yearly compounding on the same annual rate.
The Rule of 72 is a quick way to estimate when your money will double at a fixed annual interest rate. Divide 72 by your annual rate of return. For example, at a 6% annual rate, your investment will double in approximately 12 years (72 ÷ 6).