In biweekly mortgage payment, a borrower pays half of the monthly mortgage payment every other week. With 52 weeks in the year, biweekly mortgage payments adds up to 52/2, i.e. 26 half payments, or 13 full payments, each year. Since only 12 payments are required to be made per year, the 13th payment is applied directly to the principal amount due. Consequently, biweekly mortgage payments help reduce the principal balance faster than the 12 regular monthly payment plan.