Math & FinanceVerified: 2026-10-05
Simple Interest Calculator
Calculate simple interest and total maturity amount using the standard SI = (P × R × T) / 100 formula with yearly amortization schedule and compound interest comparison.
Direct Answer:Simple Interest is calculated by multiplying Principal (P) by Rate (R) and Time (T in years), then dividing by 100: SI = (P × R × T) / 100. For example, ₹1,00,000 at 7.5% per annum for 3 years earns exactly ₹22,500 in interest, giving a total maturity amount of ₹1,22,500.
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Adjust Parameters
₹1 Lakh
₹
₹1,000₹1,00,00,000
Initial loan or deposit amount
%
1%30%
Annual simple interest rate
130
Duration in years
Total Simple Interest Earned
₹22,500
Total Maturity Amount: ₹1,22,500
₹1,00,000 at 7.5% p.a. for 3 years yields ₹22,500 in simple interest.
Total Maturity Amount
₹1,22,500
Principal Deposited
₹1,00,000
Average Monthly Interest
₹625
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How Simple Interest Calculator is Calculated
Transparent mathematical formulas and assumptions used across our financial engines.
Mathematical Formula
SI = \frac{P \times R \times T}{100} \quad | \quad A = P + SI
Variables & Legend
P
Principal
R
Annual Rate
T
Time
A
Total Amount
Step-by-Step Calculation
- Compute Interest:
(P * R * T) / 100Calculates the total interest earned over the entire holding period.
- Compute Maturity:
P + SIAdds total simple interest to original principal.
- Compute Monthly Yield:
SI / (T * 12)Calculates average monthly interest yield.
Conventions & Assumptions
- In simple interest, interest is paid ONLY on the principal and never compounded.
- Most commercial bank deposits in India compound quarterly; simple interest applies to certain sovereign bonds, agricultural loans, or short-term personal lending.
Frequently Asked Questions
The formula is SI = (P × R × T) / 100, where P is Principal, R is the annual interest rate, and T is time in years. Total repayment amount is A = P + SI.