Interest Calculator
Calculate both Simple and Compound interest on your savings or loans.
Region: Global
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Quick Tip
Choose simple or compound interest.
About This Tool
Why use Interest Calculator?
This interest calculator compares simple and compound interest on the same amount, rate and time. Simple interest is charged only on the original principal, while compound interest is also charged on interest already added.
For example, 10,000 at 5% for 3 years earns 1,500 of simple interest (10,000 × 0.05 × 3). With annual compounding the balance grows to 11,576.25, so compounding earns an extra 76.25.
Key Benefits
Built for financial planning and numeric decision making
Interest Calculator is focused on loan comparison and savings planning, so you can get to the result faster.
Useful for borrowers, investors, accountants, and finance teams
The workflow is designed to support faster estimates and clear payment breakdowns without unnecessary complexity.
Privacy-first access
You can use interest calculator without a required login step, which keeps the experience faster and easier to trust.
How to use Interest Calculator
- 1
Choose simple or compound interest.
- 2
Enter the principal amount.
- 3
Add the annual interest rate and the time period.
- 4
Compare the interest earned and the final amount.
Best use cases
Use interest calculator during loan comparison when you need a quick answer without installing software.
It fits savings planning workflows where speed and clear outputs matter.
The tool is also useful for budget review when you want results in one place.
Because the interface is focused, it helps reduce manual busywork across financial planning and numeric decision making.
Interest Calculator FAQs
What is the simple interest formula?
Simple interest = P × r × t, where P is the principal, r the annual rate as a decimal and t the time in years.
When is simple interest used?
Simple interest is common for some short-term loans, car loans in certain countries and bonds that pay fixed coupons. Most savings accounts and credit cards use compounding.
Why does compound interest grow faster?
Each period's interest is added to the balance, so the next period's interest is calculated on a larger amount. The effect grows with higher rates and longer time periods.
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