📝 Formula: SI = PRT/100📅 Years / Months / Days📈 CI Comparison
Simple Interest Calculator
Calculate simple interest instantly. Enter principal, rate and time in years, months or days. Compare with compound interest.
Principal Amount
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Annual Interest Rate
1%30%
Time Period
1 yr30 yrs
Simple Interest
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SI = P × R × T / 100
Principal (P)
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Total Amount
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Monthly Interest
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Daily Interest
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Rate per Month
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Effective Return
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📝 Formula
SI = P × R × T / 100
SI = Simple Interest | P = Principal | R = Rate % per annum | T = Time in years Total Amount = P + SI | Monthly SI = P × R / (100 × 12) | Daily SI = P × R / (100 × 365)
⚖ Simple Interest vs Compound Interest (Annual)
Simple Interest earned₹0
Compound Interest earned (annually)₹0
Extra with CI over SI₹0
SI Total Amount₹0
CI Total Amount (annually)₹0
CI advantage over SI0%
Principal vs Interest Breakdown
Simple Interest
Compound Interest
Principal
ⓘ Simple interest calculations are for illustrative purposes. Actual loan or deposit interest may use reducing balance, compound, or other methods. Verify with your bank or lender for exact figures.
Frequently Asked Questions
What is the simple interest formula? +
SI = P × R × T / 100. P is the principal amount, R is the annual interest rate (%), T is the time in years. Total Amount = P + SI. For months use T = months/12; for days use T = days/365. Example: ₹1 lakh at 10% for 3 years = 1,00,000 × 10 × 3 / 100 = ₹30,000 SI, total ₹1,30,000.
Where is simple interest used in India? +
Simple interest is used in short-term personal loans, gold loans, vehicle loans (initial period), NSC and KVP savings instruments, inter-corporate deposits, and chit funds. Many banks actually use reducing-balance (EMI) method for loans, which is different — but simple interest is used as the base for understanding and comparing products.
Difference between simple and compound interest? +
SI calculates interest only on the original principal every year. CI recalculates on the growing balance — so interest earns interest. On ₹1L at 10% for 5 years: SI = ₹50,000 interest | CI (annual) = ₹61,051 interest. The longer the duration, the bigger the gap in favour of CI.
How to calculate monthly simple interest? +
Monthly SI = P × R / (100 × 12). For ₹2 lakh at 12% p.a.: Monthly = 2,00,000 × 12 / (100 × 12) = ₹2,000/month. Over 24 months total SI = ₹48,000, total amount = ₹2,48,000.
How to calculate simple interest for days? +
SI for days = P × R × D / (100 × 365), where D is number of days. For ₹50,000 at 9% for 90 days = 50,000 × 9 × 90 / (100 × 365) = ₹1,109.59. Banks may use 360 or 365 days depending on convention.
Is simple interest better than compound interest? +
As a borrower, simple interest is better — you pay less. As an investor, compound interest is better — you earn more. For long-term goals (retirement, education), always prefer investments with compound interest like mutual funds, PPF, or SCSS. For short-term borrowing (under 1 year), SI and CI are almost identical.