ðɪ ɐmˈaʊnt ʌvðə mˈʌnθli pˈeɪmənt æt ðɪ ˈɛnd ʌv mˈʌnθ ˈɛn ðæt ɪz ɐplˈaɪd tə pɹˈɪnsɪpəl pˈeɪdaʊn ˈiːkwəlz ðɪ ɐmˈaʊnt sˈiː ʌv pˈeɪmənt mˈaɪnəs ðɪ ɐmˈaʊnt ʌv ˈɪntɹɛst kˈɜːɹəntli pˈeɪd ɔnðə pɹˈiːɛɡzˈɪstɪŋ ʌnpˈeɪd pɹˈɪnsɪpəl.
The amount of the monthly payment at the end of month N that is applied to principal paydown equals the amount c of payment minus the amount of interest currently paid on the pre-existing unpaid principal.