Question 1

What is the simple interest formula?

Accepted Answer

Simple Interest = (Principal × Rate × Time) ÷ 100, where Rate is the annual interest rate as a percentage and Time is in years. The total amount payable is Principal + Simple Interest.

Question 2

What's the difference between simple interest and compound interest?

Accepted Answer

Simple interest is calculated only on the original principal for the entire period. Compound interest is calculated on the principal plus any interest already accumulated, so it grows faster over time. Most bank loans and deposits today use compound/reducing-balance methods, not simple interest.

Question 3

Where is simple interest actually used?

Accepted Answer

It's used for some short-term loans, certain fixed-term instruments, and is commonly taught as the foundational interest concept before compound interest. Always check which method a specific lender or scheme actually uses.

Question 4

Can I use a fractional time period like 1.5 years?

Accepted Answer

Yes — the time field accepts decimal values, so you can enter 1.5 years, 2.25 years, or any other fractional period.

Question 5

Does this calculator apply to Indian tax-saving instruments?

Accepted Answer

Some traditional instruments do use simple-interest-like structures, but many modern ones (PPF, bank FDs, etc.) use compound interest — check our Compound Interest Calculator for those, or talk to us about which applies to your specific investment.

Simple InterestCalculator