Benadryl Dosage Calculator for Dogs

By Łucja Zaborowska, MD
Last updated: Jul 22, 2021

The Benadryl dosage for dogs calculator is the simplest way to calculate a safe dose of Benadryl (Diphenhydramine) for your beloved dog. 🐕

No matter what you need it for - allergy, motion sickness, or anxiety - we've got you covered. We'll tell you everything you need to know about giving dogs Benadryl, a choice of different allergy medicine for dogs available on the market, and possible side effects of antihistamine for dogs.

Can you give a dog Benadryl?

The answer is both yes and no - always consult your veterinarian first! 📍

We all know that our regular food might be dangerous to our dogs - let's think about chocolate or grapes. The same goes for human medicine, as it can be pretty harmful to our pets in most situations.

What's important to check?

Let's study the example of Benadryl (or any other diphenhydramine for dogs).

  • 💊 Make sure that your tablets/syrup contains only the active substance you want to give to your dog - pay attention to any additional content that is often present in human drugs.

  • 📊 Double check if you're giving your dog the right dose! Don't follow advice for humans printed on the medication's boxes. Alway use your dog's current weight. It's especially important when you need to find liquid Benadryl dosage for dogs - carefully scan the label for the concentration of the drug, usually given in mg/mL.

  • 👨‍⚕️ Always consult your veterinarian to ensure that your dog's symptoms are not indicative of a serious disease or illness. Better to be safe than sorry!

  • 🔍 Get to know your dog's health conditions that might pose a greater risk to its life/health when combined with Benadryl. If your dog has any of the following diseases/states, it shouldn't take Benadryl:

    • Pregnancy
    • Low blood pressure
    • Any severe cardiovascular disease
    • Glaucoma
  • ☎️ Look out for all the adverse effects of Benadryl, and if they occur, consult your vet and/or set aside the medicine. If the adverse effects get severe - act quickly and call for help!

    • Lethargy
    • Dry mouth
    • Urinary retention
    • Vomiting
    • Diarrhea
    • Lack of appetite

We've equipped you with all the essential, practical knowledge about the Benadryl dosage for dogs by weight and its possible effects; time to discover our other dog tools and learn something new!

What is Benadryl used for in dogs?

Benadryl is a kind of an antihistamine drug. This kind of medication is widely used against any type of allergy. It usually works short-term.

Histamine itself is a substance released by the cells called Mast cells, which triggers our organisms' allergy reactions. Moreover, histamine plays a vital role in human brain - that's why it's also used to treat motion sickness.

Antihistamine for dogs has multiple applications - our Benadryl dosage for dogs calculator can be used for all of them.

  • Benadryl for anxiety

    Vets recommend Benadryl for dogs with severe anxiety connected to thunderstorms, traveling, or fireworks.

  • ...for allergies

    Used for mosquito, insects or snake bites, skin, food, or airborne allergies.

  • ...for motion sickness

    Caused by planes, cars, or boats.

  • ...for tumor treatment

  • ...for heartworm therapy

    The use of antihistaminic drugs protects your dog from the overreaction of their immune system caused by the heartworm elimination.

A list of Benadryl generic drugs of possible allergy pills for dogs, available on the US market:

📍 Don't give your dog any drugs without medical advice - always consult your veterinarian first!

  • Benadryl
  • Unisom
  • Sominex
  • Genahist
  • ZzzQuil
  • Nytol
  • Quenalin

How much Benadryl can I give to my dog?

Q: What dosage of Benadryl for dogs do vets generally recommend in the US?

A: General dosage is 1 mg (milligram) per 1 lb (pound).

Benadryl dosage in mg = Dog's weight in pounds * 1 mg

Q: What's the Benadryl dosage for dogs in mg per kg (kilograms)?

A: General dosage is 2.2 mg(milligram) per 1 kg (kilogram).

Benadryl dosage in mg = Dog's weight in kilograms * 2.2 mg

Let's go one step further and calculate how much Benadryl for a dog we need in milliliters (mL).

Our dog weighs 25 pounds and is extremely terrified of flying. ✈️ Our liquid Benadryl has a concentration of 12.5 mg/5 mL.

  1. Let's calculate the number of milligrams we need.

    Benadryl dosage in mg = 25 lb * 1 mg = 25 mg

  2. Let's turn milligrams (mg) into milliliters (mL).

    12.5 mg/5 mL = 2.5 mg/1 mL = 2.5 mg/mL

    We need 22 mg of Benadryl:

    25 / 2.5 = 10 mL

  3. We got it figured out! We need 10 milliliters of Benadryl.

Now you know it all! It's time for a break:

Łucja Zaborowska, MD
Your dog's weight
Benadryl dosage
In mg
Liquid (12.5 mg/5 mL)
⁍ Number of 25 mg tablets: -
⁍ Number of 12.5 mg chewable tablets: -
People also viewed…

Grain bin

Grain bin calculator helps you calculate the number of bushels or volume of grain a grain bin can store.

Leaves on tree

Tree leaves calculator is a unique tool that estimates the number of leaves growing on the tree. In fall, foliage falling force you to the endless leaves raking and collecting. How many bags do you need to prepare? How big will be the pile of the leaves? Use our calculator and solve these issues!


This millionaire calculator will help you determine how long it will take for you to reach a 7-figure saving or any financial goal you have. You can use this calculator even if you are just starting to save or even if you already have savings.

Secretary problem (Valentine's day)

Use the dating theory calculator to enhance your chances of picking the best lifetime partner.
main background