Cefalexin Dose Calculator Weight (kg) Choose Indication Skin Dosing UTI Dosing Choose Cefalexin Strength Cefalexin 125 mg/5 mL Cefalexin 250 mg/5 mL Dose in millilitres Dose in milligrams For ages 1 month to 18 years only. Calculator written by Dr Jeremy Steinberg, GP. Contact for suggestions