Knowledge Base

Simple Interest

SI = P × R × T / 100. Amount = P + SI

Interest calculated only on original principal — no compounding effect.

Used in: short-term loans, some government bonds, and inter-personal lending.

Simple interest is always less than compound interest for the same rate and tenure.

Flat rate loans use simple interest calculation — making them more expensive than they appear.

Easy to calculate mentally: ₹1L at 10% for 3 years = ₹30,000 interest = ₹1.3L total.

Pro Tip

Always check if quoted rate is simple or compound. Banks use compound for deposits but some loans quote simple (flat) rate.

Simple Interest - Complete Guide

Everything you need to know about Simple Interest and how to optimize your financial strategy.

Understanding the Formula

The core calculation is based on:

SI = P × R × T / 100. Amount = P + SI

Key Concepts & Rules

Interest calculated only on original principal — no compounding effect.

Used in: short-term loans, some government bonds, and inter-personal lending.

Simple interest is always less than compound interest for the same rate and tenure.

Flat rate loans use simple interest calculation — making them more expensive than they appear.

Easy to calculate mentally: ₹1L at 10% for 3 years = ₹30,000 interest = ₹1.3L total.

Expert Strategy

Always check if quoted rate is simple or compound. Banks use compound for deposits but some loans quote simple (flat) rate.

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