Mathematical Formula - Amortization

where:

n = number of payment periods to be amortized.
INTj = amount of PMT applied to interest in period j.
PRNj = amount of PMT applied to principal in period j.
PVj = present value (balance) of loan after payment in period j.
j = period number.
INT1 = {0 if n = 0 and payment mode is set to Begin.
|PV0 × i|RND (sign of PMT)
PRN1 = PMT – INT1
PV1 = PV0 + PRN1
INTj = |PVj –1 × i|RND × (sign of PMT) for j > 1.
PRNj = PMT – INTj
PVj = PVj –1 + PRNj