Omega-3 Calculator

Estimate your weekly EPA and DHA omega-3 intake from fish and supplements, and compare it to American Heart Association recommendations.

Results

Visualization

How It Works

EPA (20:5 n-3) and DHA (22:6 n-3) are long-chain omega-3 fatty acids incorporated into membrane phospholipids and serving as substrates for resolvin and protectin synthesis. ALA (18:3 n-3) from flax, chia, and walnuts is the plant-derived precursor; conversion to EPA averages 5-8% and to DHA under 1% (Burdge & Calder 2005). NIH AI for ALA: 1.6 g/day men, 1.1 g/day women — there is no formal RDA for EPA+DHA in the US, but global expert panels (ISSFAL, GOED) suggest 250-500 mg/day combined for cardiovascular maintenance. The American Heart Association recommends two fatty fish servings per week (~500 mg/day average); for documented coronary disease, AHA endorses ~1,000 mg/day combined. The omega-3 index (RBC EPA+DHA as % of total fatty acids) above 8% is associated with lowest cardiovascular event risk (Harris & von Schacky 2004).

The Formula

Daily Average = ((Fish Servings x 500 mg) + (Supplement mg x 7)) / 7

Variables

  • Fish Servings — Fatty fish meals per week (3.5 oz salmon ~ 1,500 mg EPA+DHA; mean across cold-water species ~500-1,800 mg)
  • 500 mg — Conservative average EPA+DHA per typical fatty-fish serving (USDA FoodData Central)
  • Supplement mg — Daily combined EPA+DHA from fish oil, krill, or algal capsules — read the label, not the total fish oil weight
  • Reference — AHA 500 mg/day general; 1,000 mg/day with coronary disease; 2-4 g/day for hypertriglyceridemia (FDA-approved indication)

Worked Example

Profile: 50-year-old with LDL-C 130, triglycerides 220, no prior MI. Eats 2 servings of canned wild salmon per week and takes a 1,000 mg fish oil capsule listing 360 mg EPA + 240 mg DHA. Weekly fish EPA+DHA = 2 x 1,200 mg = 2,400 mg; supplement EPA+DHA = 600 x 7 = 4,200 mg; total weekly = 6,600 mg; daily average = 943 mg. This exceeds the 500 mg general target and supports a target omega-3 index above 8%. For triglyceride lowering specifically, 2-4 g/day of EPA+DHA reduces TG ~25-30% (Skulas-Ray et al., Circulation 2019). REDUCE-IT showed icosapent ethyl 4 g/day (pure EPA) cut major adverse cardiovascular events by 25% in statin-treated patients with elevated TG (Bhatt 2019 NEJM); STRENGTH with mixed EPA+DHA carboxylic acid was negative — pointing to EPA-specific benefit at high dose.

Practical Tips

  • Read EPA and DHA on the supplement facts panel separately — a 1,000 mg fish oil capsule typically delivers only 300-600 mg actual EPA+DHA. Concentrated formulations provide 800-900 mg per capsule.
  • Triglyceride form (re-esterified TG, natural TG) absorbs ~70% better than ethyl ester (EE) at low-fat meals (Dyerberg 2010). EE is fine if taken with a fat-containing meal.
  • Refrigerate liquid fish oil and discard any with rancid (paint-thinner) odor. Oxidized fish oil increases markers of oxidative stress and may negate cardiovascular benefit.
  • Vegetarians and vegans: algal oil delivers DHA (and increasingly EPA) at equivalent serum response to fish oil per serving (Arterburn 2008 AJCN). Typical dose 200-300 mg DHA from algae costs 2-3x more than fish oil.
  • Doses above 3 g/day modestly raise bleeding time but, per FDA review, do not increase clinical bleeding events at doses up to 4 g/day. Disclose to surgeons and anesthesiologists pre-operatively.
  • Krill oil contains EPA+DHA bound to phospholipids (vs triglycerides in fish oil). Per-mg absorption is slightly higher but per-capsule omega-3 content is much lower, so total cost-per-mg is typically 3-5x fish oil. No proven outcome advantage.
  • Pregnancy: AHA and ACOG advise 200-300 mg DHA/day; FDA permits up to 12 oz/week of low-mercury fish (salmon, sardines, anchovies, light canned tuna) and avoidance of king mackerel, swordfish, tilefish, shark.

Frequently Asked Questions

Why is fish oil different from omega-3?

Fish oil is the carrier; EPA and DHA are the active long-chain omega-3 fatty acids inside it. A 1,000 mg fish oil capsule typically contains 300-600 mg EPA+DHA, with the remainder being other fatty acids (oleic, palmitic) and small amounts of vitamin E added as antioxidant. The supplement facts panel must list EPA and DHA milligrams separately — that is the figure that determines effective dose.

Does flaxseed give me the same omega-3 benefit?

Partially. Flax, chia, walnut, hemp, and canola oil supply ALA. Burdge & Calder 2005 review found ALA-to-EPA conversion of 5-8% in men and 9-21% in pre-menopausal women (estrogen upregulates the desaturase pathway). ALA-to-DHA conversion is under 1% in most adults. For brain and retinal DHA needs, flax alone is insufficient; algal oil is the vegan alternative for direct DHA.

Is sustained 4 g/day safe?

REDUCE-IT and JELIS used 4 g/day icosapent ethyl and 1.8 g/day EPA respectively over 5+ years with safety profile comparable to placebo, except for slightly increased atrial fibrillation in REDUCE-IT (3.1% vs 2.1%, p=0.004). FDA approves up to 4 g/day for hypertriglyceridemia. Above 5 g/day shows no added cardiovascular benefit and rises in oxidized lipid byproducts.

How does omega-3 supplementation affect blood thinning?

EPA-derived eicosanoids (TXA3, PGI3) modestly reduce platelet aggregation versus arachidonic-acid-derived TXA2/PGI2. At 3-4 g/day, bleeding time prolongs by 10-20% but does not exceed normal range in healthy users. The 2018 ASH guidance does not require pre-operative discontinuation, but disclose to your surgical team. Combined with anticoagulants (warfarin, DOACs) or antiplatelets, monitor for bruising or epistaxis.

What does the omega-3 index measure?

Sum of EPA + DHA expressed as percentage of total RBC membrane fatty acids. Harris & von Schacky 2004 showed values above 8% associated with the lowest sudden cardiac death risk; values under 4% with the highest. Most US adults score 4-5%. Roughly 2 g/day EPA+DHA for 16 weeks raises the index from 4% to 8% (Harris 2018). Order through Quest, OmegaQuant, or your physician.

Did the VITAL trial settle whether supplements help?

Mixed verdict. Manson 2019 NEJM showed 1 g/day EPA+DHA over 5.3 years in 25,871 participants did not reduce the primary composite cardiovascular endpoint or cancer. However, in subgroup analysis, fish-low consumers and African-Americans showed reduced MI and total CHD events. Translation: pharmacological doses work for high-TG patients (REDUCE-IT); 1 g/day provides marginal population-level benefit, larger benefit in those with low baseline intake.

Are there real concerns about heavy metals in fish?

Yes for predator species. Methylmercury bioaccumulates up the food chain — king mackerel, swordfish, shark, and bigeye tuna carry the highest loads (FDA/EPA). Salmon, sardines, anchovies, mackerel (Atlantic), trout, and herring are low-mercury and high in omega-3. Third-party-tested fish oil (IFOS, USP, NSF) molecularly distills off mercury, dioxins, and PCBs to undetectable levels.

Should I prefer triglyceride or ethyl ester form?

TG form (re-esterified or natural) absorbs ~70% better than EE on a low-fat meal in Dyerberg 2010 RCT. With a high-fat meal, the difference shrinks to roughly 20%. EE is the form in prescription Lovaza and most older OTC products and is cheaper. Modern concentrated supplements increasingly use rTG. If you take fish oil with breakfast oats and skim milk, switch to TG form; if with bacon and eggs, EE is fine.

Sources

Last updated: May 04, 2026 · Last reviewed: May 2026 — NutritionCalcs Editorial Team · About our methodology

More Vitamins & Minerals Calculators