| Nowadays the loan calculation method of the house fixed installment payment uses a compound interest system which is calculated monthly. Based on the compound interest system, the formula used to calculate the house installment payment generates the exponent from tens to hundreds. The aim of this study was to obtain the uncomplicated formula to estimate house installment payments. Through the analytical and empirical method using Excel the formula of the house installment payments could be derived. It was found that the maximum margin error between the calculation of the actual installment payment and the formula to estimate house installment payments less than 3.3%. If the formula is combined with the Method of Horizontal (Metris), it will make the calculation of the monthly installment payments easier and the calculation result can be obtained without using the help of a calculator. |