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Interest Calculator – Help Guide

The Interest Calculator computes simple and compound interest on savings or investments. Compound interest (earning interest on your interest) is one of the most powerful forces in personal finance.

How to Use This Tool

  1. 1

    Enter the principal amount

    Enter the initial amount you are investing or saving.

  2. 2

    Enter the interest rate

    Enter the annual interest rate (e.g., 5 for 5%).

  3. 3

    Select compounding frequency

    Choose how often interest is compounded: annually, semi-annually, quarterly, monthly, or daily.

  4. 4

    Enter the time period

    Enter how many years you want to calculate interest for.

  5. 5

    Review the results

    Compare simple vs. compound interest totals and the final balance.

Helpful Tips

  • •Daily compounding earns slightly more than monthly, which earns more than annual. Frequency matters especially for large amounts.
  • •The Rule of 72: divide 72 by the interest rate to estimate how many years it takes to double your money (e.g., 72 ÷ 6% = 12 years).
  • •High-interest savings accounts (HISA) and GICs compound interest regularly. Compare the EAR (Effective Annual Rate) not just the stated rate.
  • •Compound interest works against you on debt. Pay off high-interest debt as aggressively as you invest.

Frequently Asked Questions

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