How this instrument works
Omega-3 fatty acids (EPA and DHA) from fish oil are sometimes given to cats for joint comfort, skin and coat condition, or general anti-inflammatory support, similar to their use in dogs. This tool estimates roughly 30 mg EPA+DHA per kg of simple body weight per day — note that unlike the dog omega-3 calculator on this site, which uses metabolic body weight from two peer-reviewed dose-titration studies, this feline figure uses ordinary body weight and rests on a lower-confidence, secondary-source estimate.
Be clear-eyed about what that means: no peer-reviewed feline dose-titration study comparable to Fritsch et al. 2010 in dogs currently exists, so this ~30 mg/kg figure should be treated as a rough starting estimate, not an established science-backed dose the way the dog figure is. If you're using a labeled veterinary fish oil product formulated for cats, its own printed dosing instructions — developed for that specific formulation and concentration — should generally be preferred over this generic estimate.
This tool provides a reference range based on published veterinary sources. It is not a substitute for professional veterinary advice. Always consult your veterinarian before giving any medication, and contact your vet or an animal poison control hotline — for example the ASPCA Animal Poison Control Center, (888) 426-4435 — immediately if you suspect a toxic ingestion. Cats are also more sensitive than dogs to some supplement-related gastrointestinal upset, so starting low and asking your veterinarian before scaling up is a reasonable approach.
- Weigh your cat on a kitchen or pet scale, or use a recent veterinary weight, in kilograms.
- Read the estimated daily EPA+DHA milligram output, computed from roughly 30 mg per kg of body weight.
- Treat this figure as a rough, extrapolated estimate, not an established feline-specific dose.
- Check whether your fish oil product is labeled for cats with its own dosing instructions — prefer that if available.
- Confirm the target dose with your veterinarian, especially for kittens, senior cats, or cats on other medications.
Worked example — a 4.5 kg cat
A 4.5 kg cat (roughly 10 lb): 4.5 × 30 = 135 mg EPA+DHA per day, as a rough starting estimate. Compare that to how the dog omega-3 calculator on this site works — it uses metabolic body weight and cites two peer-reviewed dose-titration and review papers — and the difference in confidence level between the two pages should be obvious, not just the difference in formula.
A smaller 3 kg cat estimates to about 90 mg/day, and a larger 6 kg cat to about 180 mg/day. Whatever this tool returns, if your fish oil product is labeled specifically for cats, its own printed dose — built around that product's actual EPA+DHA concentration — is generally the better number to follow.
Questions
Is this omega-3 dose for cats as well-established as the dog dose on this site?
No, and this page says so deliberately. The dog omega-3 calculator rests on two peer-reviewed studies (Fritsch et al. 2010, Bauer 2011) using metabolic body weight; no comparable peer-reviewed feline dose-titration study exists, so this ~30 mg/kg cat figure is a lower-confidence, extrapolated secondary-source estimate. This tool provides a reference range based on published sources, not an established science-backed dose — it is not a substitute for professional veterinary advice.
Should I use this calculator's number or my fish oil product's own label dose?
Prefer the product's own label dose if it's formulated and dosed specifically for cats — that figure is built around that product's actual EPA+DHA concentration and any manufacturer testing behind it. Treat this calculator's ~30 mg/kg estimate as a fallback reference point, useful for comparison, not a replacement for a labeled feline product's instructions.
Can fish oil upset a cat's stomach?
Yes, particularly at higher doses or with a sudden start — vomiting, diarrhea, or reduced appetite can occur. Starting at a lower amount and building up gradually, under your veterinarian's guidance, is a reasonable approach. Always consult your veterinarian before giving any supplement, and contact them or an animal poison control hotline immediately if you suspect an overdose.
Does a flaxseed supplement give my cat the same omega-3 dose?
No. This estimate is specifically for EPA and DHA, the marine omega-3s in fish oil. Plant-based ALA from flaxseed converts to EPA/DHA very inefficiently in cats, so a flaxseed product at the same total weight will not deliver an equivalent dose. Check your product's actual EPA+DHA content per serving, not just the word “omega-3” on the label.
Is fish oil safe for cats with health conditions?
Not automatically — cats with bleeding disorders, pancreatitis, or those scheduled for surgery may need dose adjustments or to avoid fish oil altogether, since high omega-3 intake can affect clotting. Tell your veterinarian about your cat's full health history and any other medications before starting a fish oil supplement.
References
- Bauer 2011, JAVMA, Therapeutic Use of Fish Oils (PubMed)
- Fritsch et al. 2010, J Vet Intern Med (PubMed)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.