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How Much Fish Oil Should I Give My Dog?

Enter your dog’s weight and the EPA + DHA in your product to see a starting amount, the vet maximum and how many capsules that is.

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

Add the EPA and DHA on the label (mg). A “1,000 mg fish oil” capsule often has about 300 mg.

kcal

Leave 0 to estimate it (1.6 × RER).

Starting amount (EPA + DHA)549 mg

Starting amount (EPA + DHA)

549 mg

About ¼ of the maximum, per CSU

Starting amount in capsules
1.8
Vet maximum for joints (310 mg/kg^0.75)
2,196 mg
Maximum in capsules
7.3
NRC safe upper limit280 mg per 100 kcal of daily food
2,222 mg

Estimates only, not veterinary advice.

How to use the fish oil calculator

  1. Enter your dog’s weight.
  2. Add up the EPA + DHA per capsule or pump from the label (not the total “fish oil” number). A capsule sold as 1,000 mg fish oil often has about 300 mg of EPA + DHA, but check yours.
  3. Optional: enter your dog’s daily calories if you know them (the dog calorie calculator helps). Otherwise the calculator estimates 1.6 × RER.
  4. Read the starting amount, the maximum and the capsules a day.

The formula

All amounts are EPA + DHA combined.

  • Vet maximum for joints (Colorado State University Veterinary Health System, canine fish oil dosing chart): 310 mg × (weight in kg)^0.75 a day. CSU notes that not every dog tolerates the maximum.
  • Starting amount: about ¼ of the maximum, raised slowly, as CSU recommends.
  • NRC safe upper limit: 280 mg EPA + DHA per 100 kcal of the dog’s daily food (National Research Council 2006, as cited by Today’s Veterinary Practice). The calculator warns you if the joint maximum is above this.
  • Capsules = mg ÷ EPA + DHA per capsule.

Tips

  • Side effects include loose stools, vomiting, a fishy smell and weight gain from the extra calories. Fish oil can also affect blood clotting, so tell your vet before surgery.
  • Quality matters. CSU recommends products with third-party testing and a certificate of analysis.
  • Count the calories. A teaspoon of oil is roughly 40 kcal, which matters for small dogs.

Sources

  • Colorado State University Veterinary Health System: Canine fish oil dosing chart (310 mg/kg^0.75 EPA + DHA maximum for osteoarthritis).
  • National Research Council (2006). Nutrient Requirements of Dogs and Cats: safe upper limit for EPA + DHA, as cited in Today’s Veterinary Practice (2020), fish oil article.

Frequently asked questions

How much fish oil should I give my dog per day?

Count EPA + DHA, not total fish oil. Colorado State University’s vet hospital gives a maximum of 310 mg EPA + DHA per kg^0.75 a day for dogs with arthritis, and advises starting at about a quarter of that. For a 30 lb (13.6 kg) dog that is a start of about 550 mg and a maximum of about 2,200 mg. Agree the amount with your vet.

How much fish oil for a dog with itchy skin?

There is no single agreed skin dose. Vets often use omega-3s as part of treating itchy skin, but the cause (fleas, food, allergies) needs a diagnosis first. Ask your vet for a dose; the calculator shows the joint maximum and the NRC safe upper limit as outer limits.

How much omega-3 fish oil for dogs with arthritis?

CSU’s chart gives a maximum daily dose of 310 mg EPA + DHA per kg^0.75: about 1,620 mg for a 20 lb dog, 3,230 mg for 50 lb and 5,430 mg for 100 lb. CSU suggests starting at about a quarter of the maximum and raising it slowly while watching for loose stools or vomiting.

How fast does fish oil work on dogs?

Not overnight. Omega-3 fats build up in the body over weeks of steady use, so vets usually judge the effect after a month or more rather than after a few days.

Can I give my dog human fish oil?

Sometimes, but check with your vet. Look for a product that lists EPA and DHA in mg, has no added xylitol, vitamin D or other ingredients, and ideally has third-party testing for purity and freshness, as CSU advises.

Last reviewed November 3, 2026. Found a problem? Tell us.