Mortgage Amortization Formula (Basic)

A = P\frac{i(1+i)^n}{(1+i)^n - 1}


  • A = periodic payment amount
  • P = amount of principle or loan owing (subtracting any down-payments)
  • i = period interest rate
  • NOTE: if installments are monthly and interest rate is annual, need to divide by 12
  • n = total number of payments

The proof of the formula can be found here:

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