Online calculator for body fat percentage from the skinfold measurement (from calf & tricep), using the Slaughter et al. (1988) formula included as a chart in the Fitnessgram test manual. 

Alternately, the following formulas can be directly entered in Google

• Boys  (0.735*(tricep+calf))+1.0
• Girls  (0.610*(tricep+calf))+5.0