Undrawn and sitting at a zero balance, a HELOC does nothing to your DTI. Once you draw on it, the payment counts like any other debt. The specifics worth knowing: - Zero balance means no payment to count. An untapped line does not hurt your ratios, on conventional, FHA, or VA. - A drawn balance generates a payment, and that payment counts. And for revolving accounts generally, if a balance reports with no stated minimum payment, the lender imputes 5% of the balance as the monthly payment. That imputed figure only applies when there is a balance and no reported minimum. - Watch the structure of newer HELOCs. Some run a short draw period, say three years, followed by a long repayment period, say twenty-seven. A borrower can be a year and a half in and see the payment jump when the line converts to fully amortizing, which changes the number that hits your DTI. - Large draws get documented. Pull $200,000 from a $500,000 line to buy a second home and the lender has to source those funds, obtain the HELOC agreement showing how the payment is calculated, and count that draw's payment in your ratios. Short version: at zero, no impact. Drawn, it counts, and the line's terms determine how big the counted payment is.