Benadryl Dosage for Dogs
Weight-based diphenhydramine. 1 mg per lb (≈2.2 mg/kg). Liquid assumes 12.5 mg / 5 mL (2.5 mg/mL). 🕒 Dose must be repeated every 8 or 12 hours (2 or 3 times per day).
Dog's Weight
Tip: You can enter weight in g, kg, lb, or oz — results update instantly.
Dosage by weight
Rule: 1 mg/lb ≈ 2.2 mg/kg. We round only tablet counts, not the base mg.
Liquid (12.5 mg / 5 mL)
Concentration = 2.5 mg/mL. Volume = mg ÷ 2.5.
Tablets (25 mg)
Nearest whole 25 mg tablet(s). We also show rounded total mg.
Chewables (12.5 mg)
Nearest whole 12.5 mg chewable(s). Shows rounded total mg.
Step-by-step derivation
Enter a weight to see the derivation…
References & Notes
- Common veterinary rule of thumb: diphenhydramine ≈ 1 mg per pound body weight (≈ 2.2 mg/kg).
- Liquid example concentration used here: 12.5 mg per 5 mL (= 2.5 mg/mL).
- Rounded tablet counts are for convenience only—confirm with your veterinarian.
- This tool is for educational use and not a substitute for professional advice.