Simple Interest Calculator
Free simple interest calculator. Get instant results — no signup, no account. Plan and compare with confidence.
Use the Simple Interest Calculator below.
Calculate simple interest and total amount. Enter principal, annual rate, and time in years. Formula: I = P × R × T. No signup, free.
How to use Simple Interest Calculator
Enter principal
Input the initial amount (P).
Enter rate and time
Enter annual interest rate (%) and time in years.
View results
See interest (I) and total amount (P + I).
Features
- Instant results — no waiting or signup.
- Free to use — no hidden fees.
- No login or account required.
- Works on all devices — desktop, tablet, and mobile.
- Your data stays private — we do not store your inputs.
Why use this calculator
- Plan your finances with accurate estimates.
- Compare scenarios in seconds.
- Make informed decisions before you borrow or invest.
Supported browsers and devices
- All modern browsers (Chrome, Firefox, Safari, Edge).
- Mobile-friendly — use on phone or tablet.
- No app download — runs in your browser.
Frequently asked questions
Complete guide to Simple Interest Calculator
What is simple interest?
Simple interest is interest calculated only on the principal amount. It does not compound — interest is not added to the principal for future calculations. That makes it easier to compute and predict than compound interest. Simple interest is common in some short-term loans, certain bonds, and basic savings products.
Simple interest formula
Example: $10,000 at 5% per year for 3 years gives I = 10000 × 0.05 × 3 = $1,500 interest. Total = $11,500. This calculator uses the same formula; enter rate as a percentage (e.g. 5 for 5%).
I = P × R × T
I = interest, P = principal, R = annual interest rate (as a decimal or use %/100), T = time in years. Total amount = P + I.
Simple vs compound interest
- Simple interest: only on principal. Growth is linear.
- Compound interest: on principal plus prior interest. Growth is exponential.
- Over long periods, compound interest yields much more (for savings) or costs much more (for loans).
- Many banks use compound interest for deposits and reducing-balance for loans; some short-term or flat-rate products use simple interest.
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Disclaimer
Our financial calculators are for informational and educational purposes only. Results are estimates based on the inputs you provide and standard formulas. They are not financial, tax, or legal advice. We do not store or share the numbers you enter.