Which debts move when the Fed moves
Most credit cards, home equity lines of credit, adjustable-rate mortgages after their fixed period, and many private student loans have a variable rate. It's an index plus a margin. For cards and home equity lines the index is usually the prime rate, and banks move prime the day after the Fed moves. After the September 16, 2026 rise, prime went from 6.75% to 7.00%.
A fixed-rate mortgage, a fixed-rate car loan and federal student loans don't change. Leave those out of this list.
Why this shows interest, not payments
A card's minimum payment often rises only a little when its rate rises, because most of the minimum is a slice of the balance. The cost shows up as more of your payment going to interest and less coming off what you owe. Extra interest a month is the honest measure.
What to do with the number
Write down the big number. It's what your debts cost you each month to stand still. The book works through how to shrink it: the order to pay things off, balance transfers, a call to your card issuer, and the things you own that could clear a debt outright.
