Benadryl Dosage Calculator (Diphenhydramine)

Your details

Body weight of the person receiving the medication.
lb
Age in years. Children under 2 should not be given diphenhydramine without a doctor.
years
Choose the product form you have on hand.
Most children's Benadryl liquids contain 12.5 mg per 5 ml. Check your label.
Single doseStandard pediatric dose
20mg

Diphenhydramine per dose

Daily maximum120mg
Max doses per day6
Liquid volume8ml
20 mg
Low<12.5Pediatric max12.5-25Adult dose25-50Above adult max50+

Recommended dose: 20.0 mg per dose, max 120 mg per day.

  • At 20.0 kg, the weight-based dose is 20.0 mg (1 mg/kg), taken every 4-6 hours.
  • Do not exceed 120 mg in 24 hours (20.0 mg x the maximum 6 doses), and never more than the 150 mg/day label ceiling. Stop use and consult a doctor if symptoms persist beyond 7 days.
  • Diphenhydramine causes drowsiness - avoid driving, machinery operation, or alcohol while taking it.

Next stepThis calculator provides general guidance only. Always read the product label and consult a healthcare professional for medical advice.

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