12-109.Interest on judgments.

Subsection (a) doesn't set its own numeric rate. It instead points every judgment except those arising by operation of law from child support orders to the interest rate fixed in Section 2-1303. That cross-reference is the whole rule for ordinary money judgments.

Child support judgments arising by operation of law follow a different, more detailed formula in subsection (b). Interest accrues monthly, calculated by applying one-twelfth of the current statutory rate under Section 2-1303 to the unpaid child support balance as of the end of each calendar month. That balance is the total support ordered, including judgments for retroactive support, minus payments received and applied, and it excludes both that month's own unpaid amount and any interest already accrued.

The section also fixes the order in which payments get applied: regular payments go first to the current month's obligation, then any excess goes to the unpaid balance from earlier months. Federal tax refund intercepts skip that first step entirely and are applied directly to the unpaid balance instead. Only after the unpaid balance is satisfied does a payment reach the accrued interest. Because the numeric rate itself lives in Section 2-1303 rather than here, anyone checking the actual percentage needs to look at that section directly.