Simple Interest Calculator
Compute simple interest: SI = P × R × T / 100 — fast, free, private.
See how it works
Watch a quick simulation of this tool in action — no file needed.
How to use Simple Interest Calculator
Follow these steps — everything happens instantly in your browser.
- 1
Step 1. Enter the principal amount you're lending or borrowing.
- 2
Step 2. Enter the annual interest rate as a percentage.
- 3
Step 3. Enter the time period and pick the unit (years, months, or days).
- 4
Step 4. See the simple interest, total amount and a principal-vs-interest breakdown.
Why use this tool
Frequently asked questions
Everything you might want to know about simple interest calculator.
Compound Interest Calculator
See your money grow with compounding — daily, monthly, yearly.
Loan EMI Calculator
Calculate monthly EMI, total interest and payment — instant, private.
VAT / Tax Calculator
Add VAT to a net amount or strip it from a gross — any rate.
Tip Calculator
Split the bill and tip fairly — quick percentages, per-person total.