NumberCals

Simple Interest Calculator

Calculate simple interest earned on a principal amount over time.

About this calculator

The Simple Interest Calculator on NumberCals is a free, mobile-friendly tool for anyone needing to calculate simple interest earned on a principal amount over time. Enter your values in the form below and the result is computed instantly — no sign-up, no installation, no waiting.

Formula used

SI = (P × R × T) / 100

What you'll need

  • Principal Amount (e.g. 10000)
  • Annual Interest Rate (%) (e.g. 5)
  • Time (years) (e.g. 3)

What you'll get

  • Simple Interest
  • Total Amount (P + SI)
Formula
SI = (P × R × T) / 100

Frequently Asked Questions

What is simple interest? +

Simple interest is interest calculated only on the original principal, not on accumulated interest from prior periods.

When is simple interest used? +

It's used for short-term loans, some auto loans, and most personal loans where interest does not compound.

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