If you look around the Internet, you will see a lot of different recommendations for body fat percentages. As far as I can tell, this is the most authoritative, as it is based on World Health Organization and National Institutes of Health recommendations, and takes age into account. Please do not confuse these numbers with the BMI (Body Mass Index) scores, which are not the same thing.
Age-Adusted Body Fat Percentage Recommendations
Women Age Underfat Healthy Range Overweight Obese 20-40 yrs Under 21% 21-33% 33-39% Over 39% 41-60 yrs Under 23% 23-35% 35-40% Over 40% 61-79 yrs Under 24% 24-36% 36-42% Over 42%
Men Age Underfat Healthy Range Overweight Obese 20-40 yrs Under 8% 8-19% 19-25% Over 25% 41-60 yrs Under 11% 11-22% 22-27% Over 27% 61-79 yrs Under 13% 13-25% 25-30% Over 30%