Simple Interest Calculator
Calculate simple interest and total amount from principal, rate and time.
How to use Simple Interest Calculator
Three quick steps — no sign-up needed
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Step 1
Enter principal
Add the starting amount.
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Step 2
Enter annual rate and time
Set % per year and time in years.
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Step 3
Read interest and total
See simple interest and principal plus interest.
About Simple Interest Calculator
Simple Interest Calculator computes interest as principal x rate x time without compounding. Students and borrowers searching "simple interest calculator", "SI formula", or "principal rate time" need textbook-accurate results for homework and basic loans that still use simple interest.
Enter principal, annual rate (%), and time in years. Interest = P x R x T / 100 in the usual percent form. Convert months to fractional years when needed.
Most modern savings products compound; do not assume simple interest unless the contract says so. Educational calculator for clear SI maths.
Benefits of Simple Interest Calculator
Frequently asked questions
What is the simple interest formula?
Interest = Principal x Rate x Time (with rate as a decimal or percent form consistently).
How do I handle 6 months?
Use 0.5 years as time.
Is bank FD simple interest?
Many FDs compound - use the FD calculator for those products.
Does SI grow faster than compound?
No - compound interest grows faster over long periods at the same nominal rate.
Can rate be monthly?
Convert to an annual equivalent or adjust the formula carefully.