What Is Simple Interest?
Simple interest is interest calculated only on the money you start with. The principal never grows, so every year adds the same amount.
Read moreSimple Interest Calculator
Simple interest earns the same amount every year because it is always calculated on the original principal:SI = (P × R × T) / 100. Enter your values below — results update instantly and all math runs in your browser.
Interest Calculator
Results update instantly as you type — all math runs in your browser.
Principal Amount
₹10,000
The amount you started with.
Total Interest Earned
₹4,000
Interest on the original principal only.
Final Amount
₹14,000
Principal + interest after 5 years.
Growth Percent
40.0%
Total growth over the period — not an annualized return.
Dashed line marks the principal. Values are exact outputs of the calculation engine.
Growth timeline
0y5 years5 years
- Simple
- ₹14,000
- Compound
- ₹14,693
- Simple
- ₹4,000
- Compound
- ₹4,693
Value at 5 years
Principal
₹10,000
Interest earned so far
Compound advantage here
₹693
Extra interest from compounding at this point.
How simple interest works
Simple interest is the most predictable kind of interest. Whatever you deposit (the principal, P) earns a fixed fraction every year determined by the rate (R). Because the base never grows, the interest from each year is identical, and the final amount rises in a straight line.
Example: ₹25,000 at 8% for 3 years earns SI = 25,000 × 8 × 3 ÷ 100 = ₹6,000, so the final amount is ₹31,000. Compare that with the compound interest calculator to see where compounding pulls ahead.
Simple Interest Calculator — Monthly, EMI & Loan
A simple interest calculator computes the exact interest on the original principal: SI = (P × R × T) / 100. Whether you need a simple interest calculator monthly option for short-term savings, a simple interest calculator emi check for a personal loan, or a simple interest calculator loan estimate before signing a contract, this free online tool handles all scenarios instantly.
Built for Indian users, the calculator defaults to INR, supports common Indian rates (like 7.5%, 8%, or 10% per annum), and works for students preparing for board exams, borrowers reviewing loan terms, and anyone comparing a simple interest calculator india result with a compound-interest alternative.
Learn Interest the Easy Way
Short, friendly explanations written in plain language — each card links to a full explanation with worked examples.
What Is Compound Interest?
Compound interest pays interest on your interest too. Every credited amount joins the balance and starts earning on its own — growth curves upward.
Read moreSimple Interest Formula
SI = (P × R × T) / 100. Learn what each letter means and work through a full example step by step.
Read moreCompound Interest Formula
A = P(1 + r/n)^(nt) — and what n (compounding frequency) changes in the outcome.
Read morePrincipal, Rate, Time & Amount
The four building blocks of every interest calculation: what you start with, the yearly rate, how long, and what you end with.
Read moreHow Compounding Frequency Works
Annual, quarterly, monthly or daily credit — the more often interest is credited, the more it can earn on itself.
Read moreReal-Life Examples
Worked examples for students, savers and classrooms — each with steps you can copy into the calculator.
Read moreCommon Interest Mistakes
Mixing up rate periods, ignoring compounding frequency, comparing SI to CI unfairly — see the classic errors before they cost you marks (or money).
Read moreFrequently Asked Questions
What is simple interest?
Simple interest is interest calculated only on the original principal. Formula: SI = (P × R × T) / 100. Example: ₹10,000 at 8% per year earns ₹800 every year, no matter what.
What is compound interest?
Compound interest is interest calculated on the principal plus all interest already credited. Each credited amount starts earning interest itself, so growth accelerates: A = P(1 + r/n)nt.
What is the difference between simple and compound interest?
Simple interest grows in a straight line — the same amount is added every period. Compound interest grows in a curve — periods add progressively more. With identical inputs and a positive rate, compound interest is always ≥ simple interest at any point in time, with the gap widening the longer you invest.
Which formula is used to calculate simple interest?
SI = (P × R × T) / 100, where P is the principal, R the annual rate in percent, and T the time in years. For months, use T = months ÷ 12. Total amount = P + SI.
How do I calculate compound interest?
Use A = P(1 + r/n)nt, where r is the annual rate as a decimal (8% → 0.08), n the number of compounding periods per year, and t the time in years. Compound interest = A − P. Or simply use the calculator above — it applies the formula for you.
Does compound interest always earn more?
For positive rates and identical inputs, compound interest is always equal to or greater than simple interest. The difference is tiny over very short periods and grows over time. At exactly 0% interest, both methods return the principal unchanged.
How does compounding frequency affect interest?
With the same nominal annual rate, more frequent crediting (monthly vs annual) produces a higher final amount, because each credited interest starts earning sooner. The example calculator in the Compounding Frequency Explorer shows the size of the effect.
Can I calculate interest for months instead of years?
Yes. In the calculator, enter any number of years and months separately. Months are converted to fractional years (6 months = 0.5 years) and both formulas handle the fraction correctly.
Is this calculator free?
Yes — completely free, with no account, no ads-for-data and no limits. All calculations run locally in your browser.
Can I use this calculator on my phone?
Yes. The site is fully responsive and works on phones from 320px wide, tablets and desktops. Inputs, sliders, charts and results all adapt to the screen size.
Can I download my calculation results?
Yes. The results dashboard offers Copy results, Download CSV, Print and Share (a URL that encodes only the calculator inputs).
Does this calculator include taxes, fees, or inflation?
No. The calculators model the raw math of each interest method. Taxes (like TDS on FD interest), fees, rate changes and inflation are not included — real returns will differ. Treat results as pre-tax, fee-free estimates.
How accurate are the calculator results?
The formulas are the standard textbook models (SI = P·R·T/100 and A = P(1 + r/n)nt, plus continuous compounding A = Pert). The math is exact within floating-point precision and is covered by automated tests. However, results depend entirely on the assumptions you choose, and real products may credit interest differently.
What happens if the interest rate is zero?
With 0% interest there is nothing to earn: both simple and compound calculations return exactly your principal. The goal calculator will tell you that a target above the principal can never be reached at 0%.
Can I calculate interest for a custom duration?
Yes — enter any combination of years and months, and enable Advanced options to add days. Days use an act/365 day-count convention: years + months/12 + days/365.