Understanding the Alabama CS-42
Rule 32, Alabama Rules of Judicial Administration · the rules behind FairShare's Alabama calculator, computed with the official AOC workbooks (CS-42 Rev. 5/2022 and CS-42-S Eff. 6/2023).
The big picture
Alabama uses the income shares model: the guideline estimates what the parents would spend on the children if they lived together, then splits that amount in proportion to each parent's income. There are two worksheets - CS-42 for standard custody, and CS-42-S when the parents share 50/50 physical custody. Both work in whole dollars per month, exactly like the official workbooks.
Adjusted gross income (lines 1-2)
Each parent starts from monthly gross income - income from essentially any source - then subtracts child support actually paid under preexisting orders for other children (line 1a) and preexisting periodic alimony actually paid (line 1b). What remains is adjusted gross income (line 2), and each parent's share of the combined total (line 3) sets their share of everything that follows.
The basic obligation (line 4)
The combined adjusted income and the number of children look up a monthly amount on Alabama's basic child-support obligation schedule - the table realigned in September 2021, which is why FairShare's results cite the vintage "AL Realigned Sept 2021". The lookup uses the nearest $50 row; combined income below the schedule's first row uses the $250 row, and above the schedule's top ($30,000 a month) the guideline does not set an amount - that is left to the court.
Child care and health care (lines 5-10)
Work-related child-care costs and the cost of the children's health-care coverage are added to the basic obligation, and the combined total (line 7) is split between the parents by their income shares (line 8). Each parent is then credited for the child-care and health-coverage costs they actually pay (lines 9-10), so nothing is paid twice.
The self-support reserve (lines 11-13)
Since the May 2022 revision, the worksheet protects a basic amount for the paying parent's own needs: each parent keeps a $981-a-month self-support reserve, and only 85% of the income above that reserve is treated as available for support - though never less than $50. The recommended order (line 13) is the lesser of the parent's share of the obligation and that available income, so low incomes produce reduced orders down to a $50 floor. A parent with no gross income at all is set to $0.
Who pays
The worksheet computes both columns, but the recommended order applies to the parent without primary physical custody. FairShare's results name that parent and highlight the recommended row, with every line above it showing exactly where the number came from.
Shared 50/50 custody (CS-42-S)
When the parents genuinely split physical custody 50/50, the CS-42-S applies instead. It raises the basic obligation to 150% - two households cost more than one - adds both parents' child-care and health-coverage costs, and then credits each parent half of the shared-custody obligation for the time the children are with them. After those credits, the parent with the higher remaining amount pays it; when the two sides effectively cancel out, no money changes hands and FairShare says so rather than naming a payer.
The number is a starting point
The guideline amount is presumed correct, but Rule 32 lets a court deviate where applying it would be manifestly unjust or inequitable - shared or split custody arrangements and extraordinary costs are among the stated reasons - and any deviation requires written findings. If a figure surprises you, the worksheet lines on the calculator show exactly where it came from.
FairShare provides estimates for informational purposes only - not legal advice. Actual support obligations are determined by the court under your state's guidelines. See the terms.