How the EMI formula works
Your home loan EMI is a fixed monthly payment that combines both principal and interest, calculated using the reducing-balance method — interest is charged only on the outstanding principal each month, not on the original loan amount for the full tenure. That's why the same EMI has a very different principal-to-interest split in year one versus year fifteen of your loan.
Three inputs drive your EMI: loan amount, annual interest rate, and tenure. A higher loan amount or higher rate increases your EMI. A longer tenure usually lowers your monthly EMI but increases the total interest you pay over the life of the loan.