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Pet Medication Dose Calculator: mg per kg to Tablets or ml

Enter your pet’s weight, the dose your vet prescribed and the strength on the label to see how many mg, tablets or ml that is. This tool only does the arithmetic; it never suggests a dose.

Talk to your vet. This tool gives a general estimate for healthy pets, based on published veterinary guidelines. It is not a diagnosis or a treatment plan. If your pet is unwell, pregnant, on medication or has a health condition, ask your vet before changing food, supplements or care.

Enter your pet’s details

lb

Copy it from the prescription. This tool does not suggest doses.

Medicine per dose0 mg

Medicine per dose

0 mg

Enter the dose from the prescription

Tablets per dose (exact)
–
Nearest half tablet
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Medicine per day
0 mg
Weight used
13.61 kg (30 lb)
Use only the dose your vet prescribed for this pet, and check the result against the label. If the numbers do not match the prescription, call your vet or pharmacist before giving it. Never give a human medicine (such as ibuprofen, naproxen or acetaminophen/paracetamol) unless a vet tells you to: many are poisonous to dogs and cats.

Estimates only, not veterinary advice.

How to use the pet medication dose calculator

  1. Weigh your pet and enter its weight.
  2. Copy the dose from your vet’s prescription and choose its unit: mg per kg or mg per lb.
  3. Enter how many doses a day the prescription says.
  4. Choose tablet or liquid, then enter the strength printed on the label (mg per tablet, or mg per ml).
  5. Check the result against the prescription and the label before giving anything. If they do not match, call your vet or pharmacist.

The formula

Dose in mg = weight in kg × prescribed mg per kg, or weight in lb × prescribed mg per lb. One pound is 0.45359237 kg exactly.

Tablets per dose = dose in mg ÷ mg per tablet. Liquid per dose (ml) = dose in mg ÷ mg per ml.

Daily total = dose in mg × doses per day.

The calculator does not contain any medicine’s dose and never suggests one.

Tips

  • Weigh before you calculate. A dose worked out for an old weight can be wrong.
  • Read the strength carefully. Liquids can come in several strengths; mg per ml is on the label.
  • Keep medicines away from pets. If your pet ate a medicine by accident, call your vet or a pet poison line straight away.
  • Poisonings: for chocolate, see the dog chocolate toxicity calculator.

Sources

  • The weight conversion uses the exact definition 1 lb = 0.45359237 kg (NIST).
  • U.S. Food and Drug Administration (FDA), Center for Veterinary Medicine, consumer advice on human medicines and pets: human pain relievers such as ibuprofen, naproxen and acetaminophen can poison dogs and cats.

Frequently asked questions

How do I convert mg/kg to a dose for my dog?

Convert your dog’s weight to kilograms (pounds × 0.4536), then multiply by the mg per kg written on the prescription: dose in mg = weight in kg × mg per kg. Only use the dose rate your vet prescribed, and check the result with your vet or pharmacist.

Can I use this to work out a dose of a human medicine?

No. This calculator does not know any medicine’s safe dose. Many human medicines, including ibuprofen, naproxen and acetaminophen (paracetamol), are poisonous to dogs or cats. Only give a medicine and dose your vet has prescribed for your pet.

What if the dose doesn’t match a whole tablet?

Ask your vet or pharmacist. They may prescribe a different tablet strength or a liquid. Only split tablets that are scored and that your vet or the label says can be split, and never crush or split slow-release tablets.

How do I measure a liquid medicine for my pet?

Use the oral syringe that came with the medicine, or one from your vet or pharmacy, not a kitchen spoon. The calculator divides the dose in mg by the liquid’s strength in mg per ml to give the ml per dose.

My pet’s weight has changed. Should I change the dose?

Ask your vet first. Doses are prescribed for a specific weight and condition, and some medicines are not dosed purely by weight.

Last reviewed November 11, 2026. Found a problem? Tell us.