How it's calculated
dose (mg) = body weight (lb) × 1
Standard 1 mg of diphenhydramine per pound of body weight, given 2–3× daily. Liquid mL = dose mg ÷ concentration (mg/mL). Merck reference range = 2–4 mg/kg. Veterinary guidance only.
Reference ranges
| Dog weight | Benadryl dose (1 mg/lb) |
|---|---|
| 10 lb | 10 mg |
| 25 lb | 25 mg |
| 50 lb | 50 mg |
| 75 lb | 75 mg |
Common questions
How much Benadryl can I give my dog?
The common rule is about 1 mg of diphenhydramine per pound, up to 2 to 3 times a day. Confirm the dose with your vet before giving it.
Can Benadryl be given to all dogs?
No. Dogs with certain heart conditions, glaucoma, or on other medications should not take it without veterinary advice.