Dog Medication Dosage Calculator
Calculate safe OTC medication doses for your dog based on weight. Get exact dosing ranges, tablet counts, frequency, and breed-specific warnings for common over-the-counter medications.
Always consult your veterinarian before giving ANY medication to your dog. This calculator provides general dosing guidelines for informational purposes only. It is not a substitute for professional veterinary advice.
NEVER Give These to Your Dog
Reference figure only — confirm every dose with your veterinarian, especially if your dog takes other medicines or has kidney or liver disease.
How Dog Medication Dosing Works
Medication dosing for dogs is based on body weight, just like it is for humans. However, dogs metabolize drugs differently, so human doses are never safe to use directly. Each OTC medication has a specific milligram-per-pound or milligram-per-kilogram range that veterinarians consider safe for canine patients.
This calculator converts your dog's weight and the selected medication into a precise dose range using veterinary-accepted guidelines. It also shows you how that translates into common tablet sizes so you can measure accurately. Always start with the lowest effective dose and consult your vet before increasing.
Weight accuracy matters enormously. A dose that is safe for a 50-pound dog could be dangerous for a 15-pound dog. If you are unsure of your dog's exact weight, weigh them at your vet's office or use a home scale. Even a few pounds can change the recommended dose significantly for smaller breeds.
Common OTC Medications for Dogs
Benadryl (Diphenhydramine) is one of the most commonly recommended OTC medications for dogs. It helps with allergies, itching, motion sickness, and mild anxiety. The standard dose is 1 to 2 mg per pound of body weight, given every 8 to 12 hours. Use plain Benadryl only — avoid formulations with decongestants or alcohol.
Famotidine (Pepcid AC) reduces stomach acid and helps with nausea, acid reflux, and gastritis in dogs. The typical dose is 0.25 to 0.5 mg per pound, every 12 to 24 hours. It is generally well-tolerated and commonly used before and after surgery.
Glucosamine supports joint health and is widely used for dogs with arthritis or hip dysplasia. At 20 mg per pound daily, it is considered very safe for long-term use and can significantly improve mobility in older dogs.
Breed-Specific Medication Warnings
Not all medications are safe for every breed. Collies, Shelties, Australian Shepherds, and other herding breeds carry the MDR1 gene mutation, which makes them extremely sensitive to Loperamide (Imodium). Even a standard dose can cause neurological toxicity, seizures, or death in these breeds. Always have your herding breed tested for the MDR1 mutation before giving any medication.
Hydrogen peroxide should only be used to induce vomiting under direct veterinary guidance. Never use it on brachycephalic breeds (Bulldogs, Pugs, Boston Terriers) as they are at high risk of aspiration pneumonia. The maximum dose is 3 tablespoons regardless of dog size, and it should only be given once.
When in doubt, call your veterinarian first. ASPCA Animal Poison Control is available at (888) 426-4435 for emergencies. No online calculator can replace professional veterinary judgment for your specific dog's health conditions, current medications, and breed-specific risks.
Why Weight Alone Does Not Decide a Safe Dose
A weight-based figure is a starting point, not a prescription. Dogs clear drugs through the liver and kidneys, so a patient with reduced kidney function, liver disease, or dehydration may need a lower dose or a longer gap between doses at exactly the same body weight. Age matters in the same way: puppies have immature metabolism and older dogs often have reduced clearance. Concurrent medicines are the other common trap, since pairing two anti-inflammatories, or an anti-inflammatory with a steroid, multiplies the risk of gastric ulceration rather than simply adding effects. Human formulations bring a further hazard, because combination tablets often carry a second ingredient that is toxic to dogs even when the headline drug is not. Overweight dogs are dosed on lean body weight for some drugs rather than scale weight. Treat the result here as a sanity check against what your veterinarian prescribed, and confirm any new medicine with them first. Veterinary drug guidance is published by the US Food and Drug Administration at fda.gov/animal-veterinary. Updated September 2026.
Tips for Giving Medication Safely
Always use plain formulations without added flavors, xylitol, alcohol, or decongestants. Check the inactive ingredients list carefully. Xylitol, an artificial sweetener found in some liquid medications, is extremely toxic to dogs even in small amounts.
Use a pill cutter for accurate dosing when the calculated dose does not match a standard tablet size. Liquid formulations can be easier to measure for very small dogs. Hide pills in a small amount of peanut butter, cheese, or a pill pocket treat to make administration easier. Keep a medication log with dose, time, and any observed side effects to share with your veterinarian.
What to Do If You Think You Gave Your Dog Too Much
If a dose has already gone in and the number looks wrong, do not wait for symptoms and do not try to make the dog vomit unless a veterinary professional tells you to — inducing vomiting is unsafe with some drugs and with any dog that is already drowsy or unsteady. Call your own vet, an emergency clinic, or the ASPCA Animal Poison Control Center on (888) 426-4435, which is staffed around the clock. Have four things ready before you dial: your dog's weight, the exact product name and strength on the label, how much was given, and what time. Signs worth reporting immediately include vomiting, black or tarry stools, unsteady walking, pale gums, excessive drooling, or a dog that will not settle. The FDA's Center for Veterinary Medicine explains why dogs react differently to human medicines at fda.gov/animal-veterinary.
Frequently Asked Questions
What should I do if I gave my dog too much medication?
Call your vet, an emergency clinic, or the ASPCA Animal Poison Control Center on (888) 426-4435 straight away rather than waiting for symptoms. Do not induce vomiting unless a professional tells you to. Have the dog's weight, the product name and strength, the amount given and the time ready before you call.
What are the warning signs of a medication overdose in a dog?
Vomiting, black or tarry stools, unsteady walking, pale gums, heavy drooling, or a dog that cannot settle are all reasons to ring a vet immediately. Some reactions, especially to human pain relievers, show up hours after the dose rather than straight away.
Is it safe to give my dog Benadryl without asking a vet?
Benadryl (plain diphenhydramine) is generally considered safe for most dogs at 1-2 mg per pound. However, you should always consult your veterinarian first, especially if your dog has heart disease, glaucoma, high blood pressure, or is on other medications. Never use Benadryl formulations containing decongestants, alcohol, or xylitol.
Can I give my dog human Ibuprofen or Tylenol for pain?
No. Never give your dog Ibuprofen (Advil/Motrin), Acetaminophen (Tylenol), or Naproxen (Aleve). These human pain relievers can cause kidney failure, liver damage, stomach ulcers, and death in dogs even at small doses. If your dog is in pain, contact your veterinarian for dog-safe pain medication options.
Why is Imodium dangerous for Collies and herding breeds?
Many Collies, Shelties, Australian Shepherds, and other herding breeds carry the MDR1 gene mutation, which prevents them from properly processing certain drugs including Loperamide (Imodium). In these breeds, even a normal dose can cross the blood-brain barrier and cause severe neurological toxicity, seizures, coma, or death.
How do I know the exact dose if my dog is between tablet sizes?
Use a pill cutter to split tablets accurately. For very small dogs where precise dosing is critical, ask your veterinarian about liquid formulations which allow more exact measurement. Always round down to the lower dose when in doubt, and never exceed the maximum recommended dosage.
Can I give my dog Pepto-Bismol for an upset stomach?
Pepto-Bismol can be given to dogs at 1 teaspoon per 10 pounds every 6-8 hours for mild stomach upset. However, it should never be given to cats (toxic), dogs on blood thinners or NSAIDs, or dogs with bleeding disorders. It will turn stools black, which is normal. Always check with your vet first as there may be better options.
How often should I give my dog OTC medication?
Dosing frequency varies by medication. Benadryl is typically every 8-12 hours, Famotidine every 12-24 hours, Pepto-Bismol every 6-8 hours, and Glucosamine once daily. Never exceed the maximum daily dose. If symptoms persist beyond 24-48 hours, stop the medication and see your veterinarian.
Can I give my dog a human medicine if I scale the dose by weight?
No. Scaling by weight does not make a human medicine safe for a dog, because some drugs that people take daily are toxic to dogs at any dose, and combination tablets often hide a second ingredient that is. Dogs also clear many drugs far more slowly than people do, so a weight-scaled dose can still accumulate. Ask your veterinarian before giving anything from a human medicine cabinet.
Does my dog's health condition change the dose?
It can. Kidney or liver disease, dehydration, pregnancy, very young or very old age, and other medicines already being given all change how a drug is handled, and any of them may mean a lower dose or a longer interval at the same body weight. That is why this tool gives a reference figure rather than a prescription, and why your veterinarian should confirm the plan for your dog.