Technical Reference
Laboratory Standard Constants
Values are standardized mathematical representations. Clinical and empirical results may vary based on laboratory protocols, media constraints, and equipment calibration.
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Cat BMI Calculator
The Cat BMI Calculator works out your cat's Feline Body Mass Index (FBMI) using rib cage circumference and lower leg length. Enter the two measurements in cm or inches to get a numeric FBMI score, body condition category, and a WSAVA 9-point body condition score comparison. The calculator supports both metric and imperial inputs and displays a reference table of healthy, overweight, and obese FBMI ranges.
Fish Oil Dosage Calculator for Cats Logic
Target EPA+DHA (mg/day) = Weight (kg) × dose rate (mg/kg) | Dose rate: 20–90 mg/kg depending on conditionWhy "1000 mg Fish Oil" Isn't the Dose
The error I see most often is owners reading the product name ("1000 mg Fish Oil") as the dose rather than reading the EPA+DHA content from the Supplement Facts panel. An owner who gives one "1000 mg fish oil" capsule per day, assuming they are providing 1000 mg of omega-3, is typically providing only 200 to 300 mg of EPA+DHA, which may be adequate for maintenance but insufficient for therapeutic use. Always read the EPA and DHA figures separately in the supplement panel, add them together to get the EPA+DHA total, and use that number in the calculator. This mistake turns up most often when owners buy whichever fish oil is on sale without checking the EPA+DHA content per capsule, then wonder why the supplement is not producing the expected improvement after several months.
What the Fish Oil For Cats Dosage Calculator Actually Does
This tool determines your cat's daily EPA+DHA target in milligrams based on body weight and health condition, then converts that target into the number of capsules, pumps, or millilitres of your specific fish oil supplement. The dose rates are based on veterinary omega-3 guidelines published in Today's Veterinary Practice and reviewed against the National Research Council's nutrient requirements for cats. The calculator supports standard and concentrated softgels, liquid fish oil, and custom supplement inputs, since the same volume of two different products can deliver very different amounts of EPA and DHA depending on concentration.
Why EPA+DHA Is the Active Component
Fish oil contains many fatty acids, but the biologically active omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA is the primary anti-inflammatory fatty acid, competing with arachidonic acid in the eicosanoid pathway to reduce inflammatory prostaglandins and leukotrienes. DHA is incorporated into cell membranes and is particularly important for brain, eye, and heart tissue health. According to VetGirl's veterinary CE reference, EPA+DHA content varies dramatically between brands, ranging from 200 to 600 mg per 1000 mg capsule depending on formulation.
Dose Rates by Condition
| Condition | EPA+DHA Rate | Example: 5 kg cat |
|---|---|---|
| General health / coat maintenance | 20 mg/kg | 100 mg/day |
| Mild allergies, dry coat | 40 mg/kg | 200 mg/day |
| Arthritis, IBD, inflammation | 65 mg/kg | 325 mg/day |
| Heart or kidney disease (vet-supervised) | 90 mg/kg | 450 mg/day |
Maintenance supplementation for a healthy cat requires approximately 20 mg EPA+DHA per kg per day. For inflammatory conditions, allergic skin disease, osteoarthritis, or mild IBD, the therapeutic range rises to 40 to 65 mg/kg. For serious conditions such as feline hypertrophic cardiomyopathy or chronic kidney disease, some research supports doses up to 75 to 90 mg/kg per day, but at these levels supplementation should be veterinarian-supervised.
Choosing the Right Fish Oil Product for Cats
Cat-specific fish oil products such as Nordic Naturals Omega-3 Pet come in pump dispensers calibrated for pet use. Human fish oil softgels are a cost-effective alternative but require piercing the capsule for sub-capsule doses. Liquid fish oil allows the most precise dosing for small cats. Regardless of the product, refrigerate after opening and check for rancidity before each use, since rancid omega-3s form peroxides that are pro-inflammatory, the opposite of the intended effect.
Accuracy and Limitations
The dose rates used are based on published veterinary nutrition research and consistent with the WSAVA Global Nutrition Guidelines. All calculations use combined EPA+DHA content rather than total fish oil weight, the clinically meaningful figure for anti-inflammatory dosing. The calculator does not account for existing dietary omega-3 intake from the cat's primary food, which varies significantly between commercial formulations. High-dose supplementation can cause GI upset and may affect platelet function; for cats on anticoagulant medications or with bleeding disorders, always confirm the dose with your veterinarian.
Frequently Asked Questions
Muhammad Shahbaz Siddiqui
Founder, TheCalculatorsHub
How switching from total fish oil to EPA+DHA dosing resolved a cat's persistent coat issue
A reader got in touch a few months back about her 5.2 kg Bengal cat, Saffron, who had been on a fish oil supplement for four months with no visible improvement in her dry, flaky coat. The owner was giving one 1000 mg fish oil softgel per day, which she had calculated as roughly 200 mg of fish oil per kg of body weight — seemingly generous. The problem was she was dosing based on total fish oil weight rather than EPA+DHA content.
A standard 1000 mg fish oil softgel contains approximately 300 mg of combined EPA and DHA. For Saffron at 5.2 kg and a mild condition (dry coat), the target was 40 mg/kg × 5.2 = 208 mg EPA+DHA per day. Her one capsule per day was providing 300 mg EPA+DHA — which was actually close to the right amount — but the label on the specific brand she was using showed only 180 mg EPA + 80 mg DHA = 260 mg EPA+DHA, slightly below the target. Switching to one concentrated fish oil capsule (600 mg EPA+DHA) corrected the dose immediately.
Within six weeks of the corrected dosing, Saffron's coat improved noticeably — less dandruff, softer texture, and reduced shedding. The key insight was that fish oil labels list total fish oil weight prominently but bury the EPA+DHA content in smaller print. The calculator makes it explicit that the EPA+DHA number is the one that matters.