Interest Rate Calculator
Compare simple and compound interest side by side. Enter the principal, annual rate, and number of years to see the difference.
How to Use
1
Enter the principal amount.
2
Enter the annual interest rate.
3
Enter the number of years.
4
Click Calculate.
Formula
Simple
Principal x Rate x Years
Compound
Principal x (1 + Rate)^Years - Principal
Example
On $10,000 at 5% for 10 years: Simple interest = $5,000. Compound interest = $6,289. The difference of $1,289 is the power of compounding!
Why It Matters
Compound interest is called the 8th wonder of the world. Understanding the difference helps you make better financial decisions about savings, investments, and loans.
Who Uses This Calculator?
- • People comparing loan, mortgage, salary, savings, tax, or investment scenarios before making a money decision.
- • Homeowners, borrowers, employees, freelancers, and small business owners who need fast estimates without a spreadsheet.
- • Anyone who wants to understand the inputs, formula, and tradeoffs behind a financial result.
Frequently Asked Questions
What is compound interest?
Interest earned on both the original principal AND previously earned interest. It creates exponential growth over time.
How often is interest compounded?
This calculator uses annual compounding. In reality, interest may compound monthly, daily, or continuously. More frequent compounding = slightly more interest.
Which is better for me?
Compound interest benefits savers and investors. Simple interest is better for borrowers (less total interest paid).
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This calculator provides estimates for informational purposes only and is not financial, tax, or legal advice. Consult a qualified professional before making financial decisions.