Benadryl Dosage Calculator for Dogs
Enter your dog's weight to get the standard Benadryl (diphenhydramine) dose — about 1 mg per pound, every 8 to 12 hours — along with the tablet count for the formula you have and the safety warnings that matter most. It's a starting reference built to support, not replace, a quick check with your veterinarian.
Benadryl dose for your dog
Enter your dog's weight to see the dose.
Giving this more than once — or sharing care with others?
Log every dose to one shared timeline so no one in your household ever double-doses. Free, and it syncs across every caregiver's phone.
Track every dose across your householdBenadryl dosage chart for dogs (by weight)
| Weight | Dose (1 mg/lb) | Using tablets |
|---|---|---|
| 10 lb | 10 mg | Children's liquid is easier to measure |
| 25 lb | 25 mg | 1 × 25 mg tablet |
| 50 lb | 50 mg | 2 × 25 mg tablets |
| 75 lb | 75 mg | 3 × 25 mg tablets |
| 100 lb | 100 mg | 4 × 25 mg (or 2 × 50 mg) |
Give every 8–12 hours, up to 2–3 times daily. Based on the 1 mg/lb rule of thumb (Merck Veterinary Manual, 2–4 mg/kg). Always confirm with your vet.
One shared log. No accidental double doses.
In a busy household the real risk isn't the dose — it's two people giving it. SteadyTails records every dose to one shared timeline and suppresses the matching reminder on everyone else's phone. Join the waitlist for early access.
How to use this calculator safely
Weigh accurately
Dose scales with weight, so an accurate figure matters. For small pets, a precise weight and liquid formula beat guesswork.
Plain formula only
Use plain diphenhydramine — never a “-D”, cold, sinus, or nighttime product. Added decongestants or acetaminophen are dangerous.
Confirm with your vet
Treat the result as a starting reference. Your vet can weigh it against your pet's health and other medications.
Frequently asked questions
How much Benadryl can I give my dog?
The standard dose is 1 mg of diphenhydramine per pound of body weight, given every 8 to 12 hours (two to three times daily). That sits inside the Merck Veterinary Manual range of 2–4 mg/kg. Standard tablets are 25 mg, so a 25-pound dog gets one tablet and a 50-pound dog gets two. Confirm the exact dose with your vet before the first dose.
How much Benadryl for a 50 lb dog?
A 50-pound dog is usually given about 50 mg of plain diphenhydramine — two standard 25 mg tablets — every 8 to 12 hours, up to two or three times a day. Use only plain diphenhydramine, never a combination cold or nighttime product, and confirm with your veterinarian.
Which Benadryl is safe — can I use the liquid?
Only plain diphenhydramine is safe. Plain children's liquid (usually 12.5 mg per 5 ml) is useful for small dogs where splitting a tablet is imprecise. Avoid any product labelled “-D”, cold, sinus, or nighttime — those add decongestants or acetaminophen, which are dangerous for dogs.
What if I give my dog too much Benadryl?
An overdose can cause severe drowsiness or agitation, a racing heart, dilated pupils, disorientation, or in serious cases seizures. It's an emergency: call your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) right away rather than waiting for symptoms to appear.