How do you calculate dog medication dosage by weight?

Multiply your dog's weight in kilograms by the mg/kg dose rate for the specific medication. For example, amoxicillin at 10 mg/kg for a 10 kg dog equals 100 mg per dose. The calculator does this automatically and returns the dose range based on the minimum and maximum rates for each drug.

What is the correct dosage of amoxicillin for dogs?

The standard dose of amoxicillin for dogs is 10 to 20 mg/kg given every 8 to 12 hours, depending on the infection type and severity. For a 20 kg dog that is 200 to 400 mg per dose. Always complete the full antibiotic course as prescribed by your veterinarian even if symptoms resolve early.

How much Benadryl can I give my dog?

The standard diphenhydramine (Benadryl) dose for dogs is 1 mg/kg given every 8 hours. For a 10 kg dog, this is 10 mg per dose. Only use plain diphenhydramine without added decongestants such as pseudoephedrine, which are toxic to dogs. Always check with your vet before giving antihistamines.

What is the dosage of metronidazole for dogs?

Metronidazole is typically dosed at 10 to 25 mg/kg every 12 hours for gastrointestinal infections in dogs, or 15 to 25 mg/kg every 12 hours for anaerobic bacterial infections. The duration is usually 5 to 7 days. Higher doses above 60 mg/kg can cause neurological toxicity and must be avoided.

Can I give my dog ibuprofen?

No. Ibuprofen is highly toxic to dogs and must never be given. It causes gastrointestinal ulceration, kidney failure, and can be fatal even at low doses. The toxic dose in dogs is as low as 25 mg/kg. For pain management, veterinarians use carprofen, meloxicam, or other NSAIDs formulated specifically for dogs.

How much gabapentin can I give a dog?

Gabapentin for pain management in dogs is typically dosed at 5 to 10 mg/kg every 8 to 12 hours. For seizure control, doses of up to 30 mg/kg every 8 hours may be used under veterinary supervision. Gabapentin causes sedation and should not be stopped abruptly. Always use veterinary guidance for dosing.

What is the safe dose of carprofen for dogs?

Carprofen is dosed at 4.4 mg/kg once daily or 2.2 mg/kg twice daily in dogs. It should always be given with food to reduce gastrointestinal irritation. Long-term use requires periodic liver enzyme monitoring. Never use carprofen in cats, as it is not safe for feline metabolism.

What happens if I give my dog too much medication?

Overdose signs vary by drug but commonly include vomiting, diarrhoea, lethargy, loss of coordination, seizures, and changes in breathing. If you suspect an overdose, contact your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 immediately. Time is critical for many toxicities.

Is human medication safe for dogs?

Most human medications are not safe for dogs. Ibuprofen, acetaminophen (paracetamol), naproxen, and many antidepressants are toxic to dogs at standard human doses. A small number of human drugs such as diphenhydramine and certain antacids can be used in dogs at adjusted doses, but always confirm with your veterinarian before administering any human medication.

How do I calculate how much liquid medication to give my dog?

Divide the target dose in milligrams by the concentration of the liquid in mg/ml. For example, if your dog needs 50 mg of a medication that comes as a 25 mg/ml solution, divide 50 by 25 to get 2 ml. Use an oral syringe for accuracy, as household spoons are not precise enough for small doses.

Dog Dosage Calculator – Medication Dose by Weight

Dog Dosage Calculator

The Dog Dosage Calculator estimates medication doses for common veterinary drugs based on your dog's body weight in kilograms or pounds. It covers standard dosing ranges for antibiotics, anti-inflammatories, antiparasitic medications, and antihistamines used in canine care. Always confirm any calculated dose with your veterinarian before administering medication, as individual health conditions and concurrent medications can affect the correct dose.

What Is the Dog Dosage Calculator?

The Dog Dosage Calculator estimates medication doses for common veterinary drugs based on your dog's body weight, using the standard mg/kg dosing rates published for canine use. Veterinarians, veterinary nurses, and dog owners use it to work out reference dose ranges for antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), antihistamines, antiparasitic medications, and sedatives prescribed in routine canine care. The FDA's Center for Veterinary Medicine emphasises that drugs should only be used in animals under veterinary guidance, and this calculator is designed as a reference tool to support that guidance, not to replace it.

Weight-based dosing is fundamental to veterinary pharmacology because drug metabolism scales with body mass. A dose that is therapeutic in a 30 kg dog may be subtherapeutic in a 5 kg dog receiving the same tablet strength, and a dose appropriate for a large breed may cause toxicity in a toy breed. Given that tablet sizes are often manufactured for human use, calculating the precise canine dose and then working backwards to the tablet fraction or liquid volume is an essential step in safe home medication administration.

How Veterinary Weight-Based Dosing Works

Every veterinary drug has a published dose rate expressed in mg per kg of body weight (mg/kg), typically with a minimum and maximum within a therapeutic window. The minimum dose is the lowest amount expected to produce a clinical effect, and the maximum is the highest dose considered safe before adverse effects become likely. Most drugs are prescribed somewhere within that range depending on the condition being treated, the severity of the case, and the individual patient's health status.

That said, weight alone is not the only factor in dosing. Age, liver and kidney function, concurrent medications, and breed sensitivities all influence how a drug is processed. For example, MDR1 mutation carriers such as Collies and Australian Shepherds are sensitive to ivermectin and several other drugs at doses that are well-tolerated in other breeds. As a result, the calculated dose from any weight-based tool must always be reviewed by a veterinarian who knows the individual patient before administration.

Standard Dosing Ranges for Common Canine Medications

The table below lists standard dose ranges for frequently prescribed canine drugs. These figures are drawn from the Merck Veterinary Manual and represent typical practice guidelines. Always use the dose prescribed by your veterinarian, which may differ from these ranges based on your dog's specific diagnosis.

Medication	Class	Standard Dose (mg/kg)	Frequency
Amoxicillin	Antibiotic	10 to 20 mg/kg	Every 8 to 12 hours
Carprofen	NSAID (pain/inflammation)	2.2 to 4.4 mg/kg	Once or twice daily
Meloxicam	NSAID (pain/inflammation)	0.1 to 0.2 mg/kg	Once daily
Metronidazole	Antibiotic/antiprotozoal	10 to 25 mg/kg	Every 12 hours
Diphenhydramine	Antihistamine	1 mg/kg	Every 8 hours
Gabapentin	Analgesic/anticonvulsant	5 to 10 mg/kg	Every 8 to 12 hours
Doxycycline	Antibiotic	5 to 10 mg/kg	Every 12 to 24 hours

Accuracy and Limitations

The calculator applies standard published dosing ranges that represent starting points for average healthy adult dogs. It does not account for hepatic or renal impairment, which significantly affects drug clearance and requires dose reduction for many medications. Puppies under 12 weeks and senior dogs with reduced organ function both require careful dose adjustment that goes beyond simple weight-based calculation. The results should be used as a reference to confirm that a prescribed dose falls within the expected range, not as a standalone prescription tool.

Never administer human NSAIDs such as ibuprofen, naproxen, or aspirin to dogs based on a weight calculation. These drugs are disproportionately toxic to dogs relative to humans and have no safe canine dose for home use. The ASPCA Animal Poison Control Center lists ibuprofen and acetaminophen among the most common causes of canine medication toxicity reported annually.

The Dosage Mistake That Most Often Harms Dogs

The most common dosage error I see involves owners administering human-strength tablets at dog-weight-equivalent doses without accounting for excipients or formulation differences. For example, some human diphenhydramine products contain xylitol as a sweetener, which is severely toxic to dogs even in small amounts. A weight-based calculation that arrives at the correct milligram dose is meaningless if the formulation itself contains a toxic ingredient. With that in mind, always check the full ingredient list of any human medication before using it off-label in a dog, and use veterinary-formulated products wherever possible. This error turns up most often with allergy medications and pain relievers purchased over the counter before anyone looks into the inactive ingredients on the label.

Dog Dosage Calculator