Free Interest Calculator Online
Calculate simple or compound interest with detailed yearly breakdowns
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Comprehensive Interest Analysis
Simple and compound interest with full transparency
Switch between simple interest for basic calculations and compound interest for savings, investments, and loan analysis.
Choose annually, semi-annually, quarterly, monthly, or daily compounding to match your specific financial product.
View a detailed table showing how your balance and interest grow each year over the full term.
About Our Interest Calculator
Our free interest calculator lets you compute both simple and compound interest on any principal amount. Choose your compounding frequency and see a year-by-year breakdown of how your money grows. Perfect for savings planning, investment analysis, and loan comparisons.
Frequently Asked Questions
What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal amount. Compound interest is calculated on the principal plus any previously earned interest.
Compound interest grows exponentially over time, making it significantly more powerful for long-term savings and investments.
Most savings accounts and loans use compound interest, while some bonds and short-term loans use simple interest.
How does compounding frequency affect my returns?
More frequent compounding results in slightly higher returns because interest earned is reinvested sooner and begins earning its own interest.
Daily compounding yields more than monthly, which yields more than annually, though the differences diminish as frequency increases.
The effective annual rate shown by the calculator accounts for compounding frequency so you can compare products fairly.
What is the effective annual rate?
The effective annual rate (EAR) is the actual annual return after accounting for compounding. It is always equal to or higher than the stated nominal rate.
For example, a 12% nominal rate compounded monthly has an effective annual rate of about 12.68%.
EAR lets you compare interest rates across products with different compounding frequencies on an equal basis.
Can I use this for loan interest calculations?
Yes. Enter the loan principal, annual rate, and term to see how much total interest you would pay. Note that actual loan payments reduce the principal over time, which this calculator does not model.
For loan amortization with reducing principal, use our dedicated loan calculator instead.
This calculator is ideal for understanding interest growth on savings, CDs, and fixed deposits.