ToolFeather
FinanceRuns in your browser

Simple Interest Calculator

Calculate simple interest and the total amount, and compare it against compound interest for the same terms.

Quick presets

Simple Interest Calculator

₹
% p.a.
Simple interest
–
Total amount –
––
Compound interest
–
Extra from compounding
–
The formula
–
Simple vs compound over time

Educational estimate, not financial or tax advice. Returns are never guaranteed. Everything is calculated in your browser.

Runs in your browser — nothing you enter is uploaded or stored.

ToolFeather · P × R × T
Scratchpad auto-saved
Stored in this browser (localStorage)

About the Simple Interest Calculator

Simple interest is calculated only on the original principal, no matter how long the money stays invested or borrowed. That makes it easy to understand and common for short-term loans, some vehicle and personal loans, and quick back-of-the-envelope estimates.

The formula is SI = P × R × T ÷ 100, where P is the principal, R the annual rate and T the time in years. The total amount you repay or receive is simply principal plus interest. For contrast, this tool also shows what the same principal would earn under compound interest (annual compounding), where interest itself earns interest — which is why the compound figure is always higher over more than one year.

Results are estimates for planning. Real products may define time in days, compound differently, or add fees, so confirm the exact terms with your lender or bank. All maths runs in your browser.

Examples

₹1,00,000 at 8% for 5 years → simple interest ₹40,000, total ₹1,40,000.
Same terms under annual compounding → interest ≈ ₹46,933, about ₹6,933 more.
A 1-year loan gives the same interest under both methods, since compounding needs more than a year to matter.

Frequently asked questions

5 answers
What is the difference between simple and compound interest?
Simple interest is charged only on the principal, while compound interest is charged on the principal plus accumulated interest, so it grows faster over time.
When is simple interest used?
It is common for many short-term and some vehicle or personal loans, and for quick estimates. Savings products and most bank deposits use compounding instead.
Does time have to be in whole years?
No. You can enter fractional years, such as 0.5 for six months. For products that count exact days, convert days to a fraction of a year.
Why do simple and compound match for one year?
With annual compounding, interest is added only at year-end, so within a single year both methods give the same result. The gap appears from the second year onward.
Is the interest taxable?
Interest income is generally taxable in India at your slab rate. This tool shows pre-tax figures for planning.