
454 S.E.2d 697 (1995)
118 N.C. App. 171
Janet McCULLOUGH,
v.
James JOHNSON.
No. 9426DC239.
Court of Appeals of North Carolina.
March 7, 1995.
Timothy M. Stokes, Charlotte, for plaintiff appellee.
Michael S. Scofield and Mary V. Carrigan, Charlotte, for defendant appellant.
ARNOLD, Chief Judge.
Defendant argues that the trial judge's sole finding related to retroactive child support is actually a conclusion of law, and, therefore, the order for retroactive child support is not supported by the findings.
The judge's only finding related specifically to retroactive child support was "6. A reasonable amount of past child support, *698 for the period September 1, 1992, through December 31, 1992, is $500 per month." Defendant is correct in his contention that this finding is a conclusion and is therefore insufficient to support the order for retroactive child support. Determining what is reasonable requires an exercise of judgment and is therefore a conclusion of law. Plott v. Plott, 313 N.C. 63, 326 S.E.2d 863 (1985).
Findings in support of an award of retroactive child support must include the actual expenditures made on behalf of the child between September and December 1992. See Savani v. Savani, 102 N.C.App. 496, 403 S.E.2d 900 (1991). The judge must also determine that the actual expenditures were reasonably necessary. Id. Because the order for retroactive child support is not supported by sufficient findings we reverse and remand for a new hearing at which the parties may present additional evidence if necessary. Addressing defendant's lack-of-notice issue is unnecessary because defendant presumably will be properly served with notice of the new hearing.
Reversed and remanded.
WYNN and JOHN C. MARTIN, JJ., concur.
