Fish Oil Dosage Calculator for Cats

Enter your cat's weight to estimate a daily omega-3 (EPA+DHA) target in mg, then convert it to capsules or mL of your fish oil product.

Quick Facts

Method
Target EPA+DHA = dose factor × (weight in kg)^0.75
Metabolic body weight scaling; dose factor 30–75+ mg/kg^0.75. Always confirm with your veterinarian.

Your Results

Calculated
Daily EPA+DHA target
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Combined omega-3 per day
Amount of your product
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Capsules or mL per day
Metabolic body weight
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(weight in kg) ^ 0.75

Ready

Enter your cat's weight and product potency, then calculate.

About the Fish Oil Dosage Calculator for Cats

Fish oil supplements the long-chain omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which cats cannot make efficiently from plant-based omega-3. These fatty acids support skin and coat quality, joint comfort, kidney health, and modulation of inflammation. The important number is not how much oil you give, but how many milligrams of combined EPA+DHA your cat receives each day, because product potency varies enormously.

The formula this calculator uses

Omega-3 doses for cats are best scaled to metabolic body weight, which is body weight in kilograms raised to the 0.75 power. Metabolic scaling reflects the fact that smaller animals have a higher metabolic rate per unit of body mass, so a linear per-kg dose would under-dose small cats and over-dose large ones. The calculation is:

Daily EPA+DHA (mg) = dose factor × (body weight in kg)0.75

Convert pounds to kilograms first by dividing by 2.2046. The dose factor sets the intensity: roughly 30 mg/kg0.75 for everyday wellness, and up to about 75 mg/kg0.75 or more for veterinary therapeutic use in conditions such as osteoarthritis or chronic kidney disease. To turn the milligram target into a practical amount, divide it by the EPA+DHA content of one capsule or one milliliter of your product.

Worked example

A 10 lb cat weighs 10 ÷ 2.2046 = 4.54 kg. Metabolic body weight is 4.540.75 = 3.11 kg0.75. At the wellness factor of 30, the daily target is 30 × 3.11 ≈ 93 mg EPA+DHA. If your fish oil provides 300 mg EPA+DHA per mL, that is about 0.31 mL per day.

Common reference points

  • Small cat, ~6 lb (2.7 kg): metabolic weight ≈ 2.12; wellness target ≈ 64 mg EPA+DHA/day.
  • Average cat, ~10 lb (4.5 kg): metabolic weight ≈ 3.11; wellness target ≈ 93 mg/day.
  • Large cat, ~15 lb (6.8 kg): metabolic weight ≈ 4.21; wellness target ≈ 126 mg/day.
  • Therapeutic (75 mg/kg0.75) roughly 2.5× these figures — use only under veterinary direction.

Read your product label carefully

A "1000 mg fish oil" softgel is not 1000 mg of omega-3. Check the supplement facts panel for the milligrams of EPA and DHA per serving, add them together, and enter that combined figure. Human capsules are often too concentrated to split accurately for a cat, so liquid pumps formulated for pets are usually easier to dose precisely.

Frequently Asked Questions

How much fish oil should I give my cat?
Dose by combined EPA+DHA, not total oil. A common wellness target is about 30 mg EPA+DHA per kg of metabolic body weight (kg^0.75) per day — roughly 90 mg/day for a typical 10 lb cat. Veterinary therapeutic doses for joint or kidney disease can reach about 75 mg/kg^0.75 or more. Always confirm the target with your veterinarian, especially for a cat on medication or with a health condition.
Can I give my cat human fish oil capsules?
The oil itself is the same, but human capsules are often far more concentrated than a cat needs, which makes accurate dosing hard. Avoid formulas with added ingredients meant for people (such as vitamin D, garlic, or flavorings), and never use cod liver oil casually — its high vitamin A and D content can be toxic in the amounts needed to hit an EPA+DHA target. A plain fish oil or a product formulated for pets is safest.
Can a cat get too much fish oil?
Yes. Excess omega-3 can cause soft stool or diarrhea, a fishy odor, weight gain from the extra calories, and at high doses may affect blood clotting or platelet function. Introduce fish oil gradually over a week or two, watch for digestive upset, and do not exceed a therapeutic dose without veterinary supervision.
Does the calculator account for food that already contains omega-3?
No. Many complete cat foods and some treats already include EPA and DHA. The calculator estimates a total daily target, so if your cat's diet is already fortified you may need less supplemental oil. Check the food label and discuss the combined intake with your veterinarian to avoid stacking doses.

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