Simple interest calculator.
Calculate simple interest and principal plus interest for years, months or days, with an explicit day-count basis.
Simple interest inputs
I = P × annual rate / 100 × time in years. Duration: 2 years. Months use 12 per year; days use the selected 365-day basis. No interest on interest, repayments, fees, tax or changing rates.
How this simple interest calculator works
Simple interest is principal × annual percentage rate / 100 × time in years. The original principal remains the interest base throughout. Months are divided by twelve; days are divided by the selected 365- or 360-day basis. This assumes no repayments or rate changes.
A worked example
₹1,00,000 at 8% simple interest for two years earns ₹16,000 and totals ₹1,16,000. Twelve months produces ₹8,000 interest. For 90 days on a 365-day basis, interest is about ₹1,972.60.
Why does a loan EMI calculation give a different interest total?
EMI loans normally repay principal over time, so interest is charged on a declining balance. This tool keeps the principal outstanding for the whole duration. It is not an EMI, flat-rate-to-APR conversion or a bank quote; fees, taxes and payment dates are excluded.
Calculations run on your device. Review your results before exporting or sharing them.
Keep the interest basis explicit
Use the annual simple rate, even when the duration is entered in months or days. For six months, either enter 0.5 years or 6 months; both use the same time fraction. Do not divide the annual rate by twelve as well.
Changing the day basis from 365 to 360 increases interest for the same number of days. Neither choice automatically reproduces a contract's actual/actual or 30/360 calendar rules. Select the convention that matches your stated calculation rather than choosing the larger result.
Published by ToolMitra — methods and editorial approach.