Dog Medication Dosage Calculator
Calculate safe over-the-counter medication doses for your dog based on weight. Covers Benadryl, Pepto-Bismol, aspirin, and more.
Always Consult Your Veterinarian
This calculator provides general reference dosages only. Never give your dog any medication without first consulting your veterinarian. Incorrect dosing, drug interactions, and underlying health conditions can make OTC medications dangerous or fatal for dogs. When in doubt, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
Dosage Information
Benadryl (Diphenhydramine)
Standard dosage: 1 mg per pound of body weight. For a 30-pound dog, that is 30 mg per dose, given every 8-12 hours.
Use plain Benadryl only (no decongestants or added ingredients). Standard tablet is 25 mg.
Warnings & Contraindications
Do not use Benadryl-D or any formulation with pseudoephedrine or phenylephrine. Avoid in dogs with glaucoma, heart disease, or urinary retention.
Quick Reference: All Medications
| Medication | Dose | Frequency | For 30 lb dog |
|---|---|---|---|
| Benadryl | 1 mg/lb | Every 8-12 hours | 30 mg |
| Pepto-Bismol | 0.1 ml/lb | Every 6-8 hours | 3 ml |
| Buffered Aspirin | 5 mg/lb | Every 12 hours | 150 mg |
| Hydrogen Peroxide 3% | 0.045 ml/lb | Once (repeat once after 15 min if needed) | 1.3 ml |
| Pepcid AC | 0.5 mg/lb | Every 12-24 hours | 15 mg |
Medical Disclaimer
This tool is for informational purposes only and does not constitute veterinary advice. Dosages shown are general guidelines from veterinary literature and may not be appropriate for your specific dog. Always consult a licensed veterinarian before administering any medication. Drug interactions, pre-existing conditions, pregnancy, and age can all affect safe dosing. In an emergency, contact your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
About This Tool
The Dog Medication Dosage Calculator provides weight-based dosing references for common over-the-counter medications that veterinarians sometimes recommend for dogs. This tool is designed to help pet owners quickly look up standard dosages when their vet has already approved a particular medication, or when they need a reference point before calling their veterinarian. It is critically important to understand that this calculator is not a substitute for professional veterinary advice, and no medication should be given to your dog without consulting a veterinarian first.
Why Weight-Based Dosing Matters
Dogs come in an enormous range of sizes, from a 3-pound Chihuahua to a 200-pound English Mastiff. A dose that is safe for a large dog could be lethal to a small one, and a dose appropriate for a small dog would be completely ineffective for a large breed. Human medications are formulated for a relatively narrow weight range of 100-250 pounds, but dogs span a far wider range. This is why weight-based dosing, calculating the amount of medication per pound of body weight, is essential for canine medication. Even small errors in dosing can have significant consequences, particularly with medications like aspirin that have a narrow margin between therapeutic and toxic doses.
Benadryl (Diphenhydramine) for Dogs
Benadryl is one of the most commonly recommended OTC medications for dogs. At a standard dose of 1 mg per pound of body weight, it is used to treat allergic reactions, itching, hives, and mild anxiety. It can also help with motion sickness and mild sedation before stressful events. The standard 25 mg tablet makes dosing straightforward for dogs over 25 pounds. For smaller dogs, children's liquid Benadryl allows more precise dosing. The most critical safety point is to use plain diphenhydramine only. Products labeled as Benadryl-D contain pseudoephedrine or phenylephrine, which are dangerous decongestants that can cause seizures, rapid heart rate, and death in dogs.
Pepto-Bismol (Bismuth Subsalicylate) for Dogs
Pepto-Bismol can be used for short-term treatment of mild diarrhea and upset stomach in dogs at a dose of approximately 1 ml per 10 pounds of body weight. It works by coating the stomach lining and reducing inflammation. However, it contains salicylate, which is related to aspirin, so it should never be combined with aspirin or other NSAIDs. A notable side effect is that it turns stool black, which is completely normal but can be alarming if you are not expecting it. Pepto-Bismol should not be given for more than two days, and if symptoms persist, veterinary attention is needed. It is toxic to cats and should never be given to feline pets.
Buffered Aspirin for Dogs
Aspirin is occasionally recommended by veterinarians for short-term pain relief and inflammation reduction at a dose of 5 mg per pound every 12 hours. Only buffered or enteric-coated aspirin should be used, as regular aspirin is more likely to cause stomach irritation and ulcers. It is important to understand that aspirin has a relatively narrow safety margin in dogs compared to humans. Even at proper doses, it can cause gastrointestinal irritation, and prolonged use significantly increases the risk of stomach ulcers and kidney problems. Modern veterinary medicine has largely replaced aspirin with safer alternatives like carprofen and meloxicam, so aspirin should only be used when specifically recommended by your veterinarian.
Medications You Should Never Give Dogs
Several common human medications are extremely dangerous for dogs. Ibuprofen (Advil, Motrin) and naproxen (Aleve) are highly toxic and can cause kidney failure and stomach ulcers at even small doses. Acetaminophen (Tylenol) is dangerous for dogs and can cause liver failure and damage to red blood cells. Pseudoephedrine and phenylephrine, found in many cold and allergy medications, can cause seizures, elevated heart rate, and death. Xylitol, an artificial sweetener found in some liquid medications and supplements, is extremely toxic to dogs even in small amounts. Always check the inactive ingredients of any medication before considering it for your dog.
When to Skip the Calculator and Go to the Vet
This calculator is appropriate for minor, non-emergency situations where your veterinarian has already given guidance. However, you should go directly to the veterinarian or emergency animal hospital if your dog is showing signs of severe allergic reaction such as facial swelling or difficulty breathing, has ingested a known toxic substance, is experiencing persistent vomiting or bloody diarrhea, shows signs of pain such as whimpering, panting, or reluctance to move, has a known chronic health condition, or is a puppy under 12 weeks old. In emergency situations, never delay treatment to calculate a dose. Call your vet or the ASPCA Animal Poison Control Center immediately.