The ''[[Divorce Act]]'' talks about "children of the marriage." Only children of the marriage are entitled to benefit from the payment of child support.  A ''child of the marriage'' is a child of two spouses who is under the age of 19, the age of majority in British Columbia, or 19 and older but unable to withdraw from the spouses' care. Normally, adult children who are "unable to withdraw" are children who are ill or disabled, or are going to college or university, and are unable to support themselves as a result.

Under section 15.1(1), only spouses can use the ''Divorce Act'' to ask for child support orders. If the child lives with someone other than a spouse has custody of a child and that person needs child support, the that person <span class="noglossary">will</span> need to apply for child support under the provincial ''[[Family Law Act]]''.

Child support is determined by the [[Child Support Guidelines|Guidelines]] , which you can find read about in the [[Child Support]] chapter of this resource. Most of the time, child support is easy to figure out: you just look up the amount payable in the tables attached to the Guidelines based on the payor’s income of the payor, the person paying child support, and the number of children support is being paid for. Calculating child support can get more complicated when:

*#a child is 19 or older, ;*#the payor has an income of more than $150,000 per year, ;*#the payor is a stepparent,;*#one or more children live mostly with each spouse, called ''split custody'', ;*#the spouses share the children’s time equally or almost equally; or, called ''shared custody'', or*#the payment of the tables table amount would cause "undue hardship" to either the recipient of child support payor or the payor of spouse receiving child support.