Benadryl Dosage Calculator: Determine Safe Diphenhydramine Doses by Weight

Calculate Your Benadryl (Diphenhydramine) Dosage

Enter the patient's body weight.
Select patient type to guide dosage recommendations.
Enter the strength of your liquid Benadryl (e.g., 12.5 mg for a 5 mL spoonful).

Confidently calculate the correct Benadryl (diphenhydramine) dosage for both children and adults. Our calculator helps you determine the appropriate amount based on body weight and medication concentration, ensuring safe and effective treatment for allergies, colds, and insomnia symptoms. Prevent common dosing errors with this essential tool for home use.

Formula:

The Benadryl (diphenhydramine) dosage for children (6-11 years) is typically 12.5 mg per dose. For adults (12+ years), a common dose is 25-50 mg per dose, often guided by weight (approx. 0.5 mg/kg). The formulas used are:

Dose (mg) = Recommended Dosage for Age Group (mg)

Volume (mL) = (Dose (mg) / Concentration (mg/mL))

Where:

  • Recommended Dosage for Age Group (mg): Based on age (e.g., 12.5 mg for children 6-11; 25-50 mg for adults 12+).
  • Weight (kg): Patient's weight in kilograms (used to refine adult dosage within its range).
  • Concentration (mg/mL): Strength of the liquid Benadryl medication (e.g., 12.5 mg/5 mL = 2.5 mg/mL).

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