Simple Interest Calculator India RBI Guidelines 2025
How simple interest is calculated for personal loans, FDs, and NSC in India. RBI guidelines on interest calculation methods and how to use the SI formula.
Simple Interest (SI) is calculated as SI = (P × R × T) / 100, where P = Principal, R = Rate of Interest (% per annum), and T = Time in years. This flat-rate method is used for NSC (National Savings Certificate), some personal loans, and certain term deposits — though most modern bank products use compound interest.
For a ₹1 lakh investment at 7.5% for 3 years: SI = (100000 × 7.5 × 3) / 100 = ₹22,500. Total at maturity = ₹1,22,500.
SI vs EMI: Know the Difference
Simple Interest treats interest as a fixed amount on the original principal. EMI (Equated Monthly Instalment) loans use reducing balance — interest is recalculated on the outstanding principal each month. EMI loans cost less in total interest than flat-rate loans at the same stated rate.
Use our simple interest calculator india rupees for flat-rate calculations. For EMI-based loans, use our emi calculator india loan. To understand your marks: marks percentage calculator india.