Fish Mercury Calculator — Weekly Methylmercury Intake
Select a fish species, enter how many servings you eat per week and your body weight, and see your estimated weekly methylmercury intake versus the EPA reference dose — so you can make informed choices about how much fish to eat.
Fish species
kg
Methylmercury consumed per week from fish at this serving frequency
- 1
Mercury per serving
113.4 g × 0.128 μg/g = 14.5152One FDA serving = 4 oz (113.4 g cooked). - 2
EPA weekly limit for your weight
0.7 μg/kg × 70 kg = 49 - 3
Weekly methylmercury intake
2 servings × 14.5152 μg = 29.03
How does this calculator work?
Weekly mercury intake = servings × 113 g × species concentration (μg/g). Compare to your EPA limit = 0.7 μg/kg body weight/week. Low-mercury fish (salmon, shrimp, light tuna) are safe at 2–3 servings/week; avoid swordfish, shark and king mackerel for frequent meals. Mercury values are FDA 2024 means — editable as needed.
Formula
How this is calculated
Mercury enters the food chain mainly as methylmercury, the organic form that accumulates (bioaccumulates) in fish tissue — more in longer-lived, larger predatory fish such as swordfish and shark, less in shorter-lived species such as salmon and shrimp. The FDA measures mean methylmercury concentrations in commercially sold fish; the values used here are from the 2024 FDA monitoring data and are expressed in micrograms per gram (μg/g, equivalent to parts per million).
This calculator multiplies the number of servings per week by the FDA standard serving weight of 4 oz (113.4 g cooked) and by the species's mean concentration, giving total weekly methylmercury intake in micrograms. It then compares that intake with the EPA oral reference dose of 0.1 μg/kg body weight per day (= 0.7 μg/kg/week), which is the level estimated to be without appreciable risk of adverse effects over a lifetime.
Important limitations: actual mercury levels in individual fish vary considerably around the mean; cooking method has little effect on methylmercury content; canned tuna levels differ by variety (light vs albacore). Pregnant women, nursing mothers and young children face the highest risk from methylmercury and should follow the current FDA/EPA advice to eat 2–3 servings per week of low-mercury fish and avoid the highest-mercury species. This tool is informational only and not a substitute for medical or dietary advice.
Frequently asked questions
Salmon, shrimp, tilapia, catfish, and pollock have the lowest mercury concentrations and are considered "best choices" by the FDA — up to 2–3 servings per week are generally safe for most adults. Canned light tuna is also low and acceptable at up to 2–3 servings/week.
High methylmercury intake can damage the nervous system. The developing brain in fetuses and young children is most vulnerable, which is why pregnant women are advised to avoid high-mercury fish. In adults, chronic overexposure can impair coordination, vision, hearing and speech. For most people eating moderate quantities of low-mercury fish, the risk is very low.
The EPA reference dose is a conservative health-protective threshold, not an absolute cutoff. Occasional exceedances for healthy adults are not necessarily harmful — cumulative and chronic exposure is what matters. However, if you exceed the limit regularly, especially with high-mercury species, consider substituting lower-mercury alternatives.
Also known as
TG we-Calculate Editorial Team. (2026). Fish Mercury Calculator — Weekly Methylmercury Intake [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/fish-mercury-calculator
TG we-Calculate Editorial Team. "Fish Mercury Calculator — Weekly Methylmercury Intake." TG we-Calculate. 2026. https://we-calculate.com/calculator/fish-mercury-calculator.
TG we-Calculate Editorial Team, "Fish Mercury Calculator — Weekly Methylmercury Intake," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/fish-mercury-calculator
@misc{wecalculate_fish_mercury_calculator, title = {Fish Mercury Calculator — Weekly Methylmercury Intake}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/fish-mercury-calculator}}, year = {2026}, note = {TG we-Calculate} }
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