
485 S.E.2d 750 (1997)
268 Ga. 10
HOODENPYL
v.
REASON.
No. S97A0686.
Supreme Court of Georgia.
May 5, 1997.
*751 Clifton M. Patty, Jr., Ringold, for Sheena Renae Hoodenpyl.
Ronald C. Goulart, Fort Oglethorpe, for Raymond Eugene Reason.
FLETCHER, Presiding Justice.
We granted Sheila Hoodenpyl's application to appeal to consider whether O.C.G.A. § 19-6-15 authorizes a trial court to calculate the amount of child support owed based on all the children of a party, rather than the children for whom support is being determined. Because Ehlers v. Ehlers[1] made clear that in determining child support the trial court must calculate the initial percentage of gross income based only on the children for whom it is determining support, and the court below failed to follow Ehlers, we reverse.
Hoodenpyl and Raymond Reason were formerly husband and wife. When they divorced in 1990 Hoodenpyl received custody of the couple's two children and Reason was ordered to pay child support. In February 1996, Hoodenpyl sought an upward modification of child support for the two children based on a change in circumstances. The trial court granted the upward modification, but calculated the guideline percentage of gross income based on three children because Reason subsequently had another child with his second wife. Having calculated the amount of gross income to be used for support, the court then divided that amount on a pro rata basis and made an award of two-thirds of the total to Hoodenpyl's two children.
1. We previously considered this same issue in Ehlers.[2] There, this court held that "[t]he guideline percentage of child support found in O.C.G.A. § 19-6-15(b) cannot be based upon the total number of children the obligor must support."[3] In Ehlers, this court made clear that the statute requires that the guideline calculation be based only on the number of children for whom child support is being determined.[4] Therefore, the trial court erred in concluding that the applicable percentage of income was the percentage applicable for three children rather than the two children for whom the court was determining support.
2. Once the guideline percentage is determined, the trial court may vary the range upon a written finding that the presence of one or more enumerated special circumstances makes the presumptive amount of support excessive or inadequate.[5] One of the enumerated circumstances is a party's support obligations to another household.[6] The mere fact of additional children, however, will not justify a reduction in the guideline range. The essential question is whether this additional support obligation renders the presumptive amount of support excessive. The trial court may answer this question only by examining all the relevant circumstances, including the sources of support *752 for the new household. By considering not only the fact of additional children, but also the circumstances relevant to the support needs of those children, the trial court will be able to make a determination of support that best balances the children's needs and the parent's ability to pay.[7]
Judgment reversed and case remanded for further proceedings consistent with this opinion.
All the Justices concur.
NOTES
[1]  264 Ga. 668, 449 S.E.2d 840 (1994).
[2]  264 Ga. at 668, 449 S.E.2d 840.
[3]  Id. at 670-71, 449 S.E.2d 840.
[4]  Id. at 670, 449 S.E.2d 840.
[5]  O.C.G.A. § 19-6-15(c) (1991 and 1996 Supp.).
[6]  Id. at (c)(6).
[7]  See Arrington v. Arrington, 261 Ga. 547, 407 S.E.2d 758 (1991).
