Dog Deworming Calculator
A free dog deworming calculator that works out the dewormer dose by weight — fenbendazole (Panacur/Safe-Guard), pyrantel pamoate (Nemex) and praziquantel — in mg, mL or grams, plus a puppy and adult deworming schedule and a Safe-Guard weight chart.
| Deworming | When |
|---|
| Weight | Granules/day | 10% liquid/day | 3-day granules |
|---|
How to Calculate a Dog’s Deworming Dose
The tabs above give a general Dewormer Dose calculator for any product, dedicated Fenbendazole and Pyrantel calculators with the right built-in rates, a puppy-to-adult Schedule, and a Safe-Guard chart by weight.
The Deworming Dosage Formula
Every weight-based dewormer dose follows the same three steps:
2. Total dose: milligrams = weight (kg) × dose rate (mg/kg).
3. Amount to give: mL = total mg ÷ mg per mL; or grams = total mg ÷ mg per gram; or tablets = total mg ÷ mg per tablet.
Worked example with fenbendazole: a 20 kg dog at 50 mg/kg needs 20 × 50 = 1,000 mg a day. With the 22.2% granules (222 mg/g) that is about 4.5 g a day for 3 days; with a 10% (100 mg/mL) liquid it is 10 mL a day. Getting the concentration right is the step people most often miss.
Fenbendazole (Panacur / Safe-Guard) Dosing
Fenbendazole is the broad-spectrum dewormer in Panacur and Safe-Guard, effective against roundworm, hookworm, whipworm and Giardia. The standard dose is 50 mg/kg once daily:
| Target | Course |
|---|---|
| Roundworm, hookworm, whipworm | 50 mg/kg daily × 3 days |
| Giardia | 50 mg/kg daily × 5 days |
| Whipworm (repeat protocol) | 3-day course, repeat at 3 weeks and 3 months |
Pyrantel Pamoate (Nemex / Strongid) Dosing
Pyrantel pamoate treats roundworm and hookworm, has a very wide safety margin and is the usual choice for young puppies. The dose is about 5 mg/kg (2.27 mg/lb) as a single dose, repeated in 2 weeks to catch worms that hatch after the first dose. Concentrations vary: a common over-the-counter liquid is 4.54 mg/mL, which comes out to roughly 1 mL per 2 lb (5 mL per 10 lb), while veterinary Strongid-T is 50 mg/mL. Always check your bottle, because that tenfold difference completely changes the volume.
Dog Deworming Schedule
How often to deworm depends mostly on age. The widely used schedule is:
| Life stage | Deworming frequency |
|---|---|
| Puppies | At 2, 4, 6, 8 and 12 weeks, then monthly until 6 months |
| Adult dogs | Every 3 months (quarterly), or fecal-test-led every 6–12 months |
| Pregnant dogs | As advised by your vet, often from late pregnancy through nursing |
| High-risk dogs | More often — hunting, scavenging, raw diet or around young children |
How many doses? It depends on the product. A fenbendazole course is one dose a day for 3 days; pyrantel is one dose repeated after 2 weeks. If your dog is on a monthly heartworm preventive that also covers intestinal worms, you may need less separate deworming — check with your vet. Many vets now favour fecal testing over blanket routine treatment in low-risk adult dogs.
Deworming Safely
A few rules keep deworming safe and effective. Weigh your dog on a scale rather than guessing — the most common dosing error is a wrong weight. Match the product to the parasite: pyrantel does not treat whipworm or tapeworm, and a fecal test confirms what you are dealing with. Don’t use livestock or horse products on a dog without veterinary guidance, as the concentrations are made for far larger animals. And take special care with herding breeds (collies, Australian shepherds and relatives) that may carry the MDR1 gene mutation, which makes some antiparasitics dangerous at normal doses. When in doubt, ask your vet.
Frequently Asked Questions
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