Often, jurisdictions combine the incomes of both parents and then require each parent to contribute a percentage of their income to their children's support. (wisegeek.com)
However, for states that may calculate income based on the combined income of both parents, one parent may be deemed to be the primary custodian for child support payments. (thespruce.com)
For that reason, the Vermont guidelines base the child support calculation on the combined income of both parents. (vermontjudiciary.org)