BACKGROUND Compared with guidelines for the quantity of topical corticosteroids to apply in adults, standards for the use of topical corticosteroids in children are not well described. OBJECTIVE To devise simple-to-use guidelines for topical corticosteroid quantities needed in infants, children, pre-teens, and adults. METHODS We determined body surface area (BSA) using mean heights and weights in order to calculate the appropriate quantities of medication to be prescribed. RESULTS As a rough estimate, infants require one-fifth of adult doses, children two-fifths of adult doses, and adolescents two-thirds of adult doses. However, the assessment of BSA may vary considerably between clinicians. Patients may also vary in how thickly they apply topical medication. CONCLUSIONS A simple guideline for how much topical corticosteroid to prescribe may facilitate the treatment of young children with skin disease.