How this instrument works
For people with known coronary heart disease, the American Heart Association's Nutrition Committee has recommended consuming about 1 gram per day of combined EPA and DHA, the two main long-chain omega-3 fatty acids found in fish oil — either through fatty fish or, when that's impractical, a supplement, ideally in consultation with a physician (Kris-Etherton PM et al., Circulation. 2002;106(21):2747-2757). This calculator is scoped to that specific, citable target, not a general recommendation for everyone.
That narrow scope is deliberate. Per the NIH Office of Dietary Supplements, there is no formally established RDA (Recommended Dietary Allowance) for EPA and DHA specifically in the general healthy population — only an Adequate Intake figure for ALA, a different, shorter-chain omega-3. Because no single authoritative general-population EPA+DHA figure exists to calculate against, this calculator doesn't attempt one; it sticks to the one condition-specific target that does have a clear, citable source.
The arithmetic itself is simple: divide the target in grams by how many milligrams of EPA+DHA a single capsule or serving actually provides, after converting the target to milligrams. The part that takes real label-reading is the second number — real fish oil products vary enormously in EPA+DHA content per capsule, and capsule size or total fish oil weight on the front of the bottle is not the same thing as the combined EPA+DHA content printed in the supplement facts panel.
- Enter the target EPA+DHA amount in grams per day (defaults to 1 g/day, the AHA figure for known heart disease).
- Enter the EPA+DHA content per capsule in milligrams, read directly from your specific product's supplement facts panel — not the total fish oil weight.
- Read the number of capsules needed per day to reach the target.
- Confirm this target applies to you: it's specifically for people with known heart disease, and your own cardiologist or physician may have different guidance based on your situation.
Worked example — three products, same 1 g/day target
With the default 1 g/day target and a product that provides 1000 mg of combined EPA+DHA per capsule, the math is (1 × 1000) ÷ 1000 = 1 capsule per day — a full gram in a single capsule, which is on the higher-concentration end for over-the-counter fish oil.
The same 1 g/day target with a weaker 500 mg-per-capsule product needs (1 × 1000) ÷ 500 = 2 capsules per day to reach the same total. This is the scenario worth double-checking against your own bottle, since many standard fish oil capsules provide well under 500 mg of combined EPA+DHA despite looking similar in size to a stronger product.
A 300 mg-per-capsule product needs (1 × 1000) ÷ 300 ≈ 3.3 capsules per day for the same 1 g target — illustrating how far capsule count can swing based on concentration alone, which is exactly why checking the supplement facts panel matters more than counting capsules or judging by softgel size.
Questions
Why 1 gram per day specifically?
That figure comes from the American Heart Association's Nutrition Committee, which reviewed the cardiovascular evidence for omega-3 fatty acids and recommended about 1 g/day of combined EPA and DHA for people with known coronary heart disease (Kris-Etherton et al., Circulation, 2002). It's one of the few omega-3 intake figures with a specific, citable clinical source, which is why this calculator uses it as the default rather than a general wellness number.
Why doesn't this calculator have a target for people without heart disease?
Because no formally established RDA exists for EPA and DHA in the general healthy population — the NIH Office of Dietary Supplements notes that only an Adequate Intake figure exists, and that's for ALA, a different omega-3 fatty acid found mainly in plant sources like flaxseed. Rather than presenting an invented general-population figure, this calculator stays scoped to the one target — the AHA's heart-disease-specific figure — that has clear clinical backing.
Where do I find the EPA+DHA content per capsule for my product?
Check the supplement facts panel on the bottle, not the front-label claim. Products often advertise a large 'fish oil' number on the front (for example, 1000 mg or 1200 mg fish oil) while the supplement facts panel further down lists a smaller combined EPA+DHA figure — sometimes several hundred milligrams less — because fish oil contains other fatty acids and components beyond just EPA and DHA.
Does capsule size tell me how much EPA+DHA is inside?
No. Two products with visually identical softgel capsules can differ substantially in EPA+DHA concentration — one might concentrate more EPA+DHA per capsule through processing, while another dilutes it with more filler oil. The only reliable number is the one printed on that specific product's supplement facts panel, which is why this calculator asks for it directly rather than estimating from capsule size or count.
I'm already on a statin or have high triglycerides — does 1 g/day still apply to me?
Not necessarily. The 1 g/day figure this calculator defaults to is a general recommendation for known heart disease, but individual guidance can differ — for example, people with very high triglycerides or those on certain statin therapies sometimes have different omega-3 recommendations from their physician. Confirm your specific target with your own cardiologist or physician rather than relying on the default alone.
Is this calculator giving me medical advice?
No. It performs one specific unit conversion — target grams of EPA+DHA divided by your product's milligrams per capsule — using a published clinical target for a specific population (known heart disease). It doesn't diagnose, assess your individual risk, or replace a conversation with your physician about whether fish oil supplementation, and at what dose, is right for you.
References
- Kris-Etherton PM et al. — Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and CVD. Circulation. 2002;106(21):2747-2757
- NIH Office of Dietary Supplements — Omega-3 Fatty Acids, Health Professional Fact Sheet
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.