Loan & EMI_
Work out a monthly payment, solve for how much you can borrow, or back out the interest rate — then read the full amortization schedule. Switch between dollars, euros, and rupees.
How the numbers are worked out
For a fixed-rate loan with equal monthly instalments (the EMI model), each payment is split between interest on the outstanding balance and repayment of principal. The standard formula for the monthly payment is:
where P is the principal (loan amount), n is the number of monthly payments, and r is the monthly interest rate — the annual rate divided by 12 (so 9% per year is 0.75% per month). When the rate is 0%, the payment is simply P ÷ n.1
The other two modes
Loan amount rearranges the same equation to solve for P from a payment you can afford. Interest rate can't be isolated algebraically, so the calculator solves it numerically (by bisection) — finding the rate that makes the formula reproduce your payment. That mode needs your total payments to exceed the principal; otherwise no positive rate fits.
Amortization
The schedule shows, month by month, how each payment divides into interest and principal and how the balance falls to zero. Early payments are mostly interest; later ones are mostly principal — which is why total interest is so sensitive to the rate and term.2
Further reading
- Investopedia. Equated Monthly Installment (EMI). investopedia.com
- Investopedia. Amortization. investopedia.com