How to use the fish consumption calculator
The tool needs three inputs and takes about ten seconds. Start with the audience buttons if you want a quick preset, then change any number to match your own meal.
Enter your weight
Body weight sets your daily mercury limit. Type it in pounds or kilograms. The Adult, Teen, Child, and Pregnant buttons load a typical weight and serving size for you.
Pick your fish
Choose from 13 fish and shellfish. Canned light tuna is selected by default because it is the most common pantry fish.
Set your serving
Use the size of your real plate. Eight ounces is the EPA standard adult meal. The FDA uses 4 ounces, so try both and compare.
Caught the fish yourself? Select "My own catch" and a ppm box appears. Type the value from your state advisory or a lab report, and the calculator uses it in place of the average. The "Compare every fish at once" panel under the gauge ranks all 13 fish for your weight and serving, which helps when you plan a week of meals.
How to read your result
The big number is the count of servings you can eat in one week before you pass the EPA mercury limit. The curved gauge fills as the number grows, and its color tells you how much room you have.
| Gauge color | Servings per week | What it means |
|---|---|---|
| Green | 2 or more | A low-mercury choice at this serving size. |
| Amber | 1 to 2 | Eat it in moderation and mix it with other fish. |
| Red | Less than 1 | Keep it rare and choose a lower-mercury fish most weeks. |
One point trips people up. A result of 9.5 salmon meals does not mean you should eat 9 or 10 of them. It means mercury would not be your limiting factor. Variety, calories, and the FDA's 2 to 3 servings a week matter more for daily eating. Share your result with the Copy button if you want to send it to a partner or a fishing buddy.
How the fish consumption calculator works
The math starts with the EPA reference dose for methylmercury. That dose is 0.1 micrograms per kilogram of body weight per day. EPA built it with a tenfold safety margin, so a small overshoot on one day is not an emergency. Mercury also clears from the body slowly, with a half-life of roughly 50 days, which is why the calculator looks at a full week.
The calculator follows four steps.
- Convert your weight to kilograms. Pounds times 0.4536 gives kilograms.
- Multiply by 0.1 micrograms and by 7 days to get your weekly limit in micrograms.
- Convert your serving to grams. Ounces times 28.35 gives grams. Then multiply by the fish's ppm to get the micrograms in one serving.
- Divide the weekly limit by the micrograms per serving. The result is your servings per week.
Here is a worked example. A 150-pound adult weighs about 68 kilograms, so the weekly limit is about 48 micrograms. One 8-ounce meal is 227 grams. At 0.126 ppm for canned light tuna, that meal holds about 29 micrograms. Divide 48 by 29 and you get 1.7 meals a week.
Size changes the answer fast. A 40-pound child weighs about 18 kilograms, so the weekly limit drops to roughly 13 micrograms. A 2-ounce serving of the same tuna holds about 7 micrograms, which gives 1.8 servings. The portion is a quarter of the adult one, yet the weekly count is almost the same. The table in the next section runs the same formula for three common body sizes.
Sample results by body size
These rows show what the calculator returns for three common setups. They use the same averages as the tool, rounded the same way. Your own numbers will differ with your weight and plate size.
| Fish | Mercury (ppm) | Child, 40 lb, 2 oz | Adult, 150 lb, 4 oz | Adult, 150 lb, 8 oz |
|---|---|---|---|---|
| Shrimp | 0.009 | 25 | 47 | 23 |
| Tilapia | 0.013 | 17 | 32 | 16 |
| Salmon | 0.022 | 10 | 19 | 9.5 |
| Catfish | 0.025 | 9.0 | 17 | 8.4 |
| Trout (freshwater) | 0.071 | 3.2 | 5.9 | 3.0 |
| Cod | 0.111 | 2.0 | 3.8 | 1.9 |
| Canned light tuna | 0.126 | 1.8 | 3.3 | 1.7 |
| Halibut | 0.241 | 0.9 | 1.7 | 0.9 |
| Canned albacore tuna | 0.350 | 0.6 | 1.2 | 0.6 |
| Yellowfin tuna | 0.354 | 0.6 | 1.2 | 0.6 |
| King mackerel | 0.730 | 0.3 | 0.6 | 0.3 |
| Shark | 0.979 | 0.2 | 0.4 | 0.2 |
| Swordfish | 0.995 | 0.2 | 0.4 | 0.2 |
Servings per week at the EPA mercury limit. Rounded to one decimal under 10.
The gap between rows is the useful part. Canned light tuna and albacore both come in cans, yet albacore lets an adult eat about half as many meals. Cod and halibut look alike on a menu, but halibut carries twice the mercury.
Mercury levels in popular fish
Mercury builds up as it moves up the food chain. Small fish eat plankton and insects. Big predators eat the small fish, so they store the most. The bars below show FDA monitoring averages in parts per million. Shrimp sits at 0.009 ppm, while swordfish sits at 0.995. That is a gap of about 110 times.
Green bars fall below 0.15 ppm, amber bars run from 0.15 to 0.4, and red bars sit above that. The same ranking drives the FDA's three advice groups. Best Choices cover the lowest fish and allow 2 to 3 servings a week. Good Choices allow one serving. Fish in the "avoid" group include king mackerel, shark, and swordfish. Want to see where the numbers come from? Jump to where the data comes from.
Who should use the calculator
Most adults reach the mercury limit only with tuna, halibut, or the big predators. The Adult button loads 150 pounds and an 8-ounce meal. Heavy tuna eaters should compare light and albacore tuna in the table above.
Smaller bodies reach the limit sooner. Enter the child's real weight and a 1 to 4 ounce serving. The serving sizes by age below give a size for each stage.
Mercury reaches a developing baby, so the stakes are higher. The Pregnant button loads a 4-ounce serving. Follow your doctor's advice first, and read the FDA picks below.
Local waters can run well above store-bought averages. Check your state advisory, then use "My own catch" with a real ppm value. Your state health or environment department posts the notice for each water body.
People who eat fish for heart health also use the tool. If you want omega-3 without a mercury penalty, salmon and freshwater trout are rich in omega-3 and sit in the green zone above. The Dietary Guidelines for Americans suggest at least 8 ounces of seafood a week for adults, so cutting fish out is rarely the right fix.
What the calculator does not cover
This tool measures methylmercury and nothing else. It does not score PCBs, dioxins, or PFAS, which can matter for fish from some lakes and rivers. PCBs sit in fat and skin, so trimming helps with them. Removing the skin and the fatty belly strip, then cooking on a rack so fat drips away, are the usual steps. Trimming does nothing for mercury, which lives in the muscle.
The numbers are averages. One large swordfish can test higher than 0.995 ppm, and one small one can test lower. Cooking also changes the picture. Fish loses water in the pan, so a cooked ounce holds more mercury than a raw ounce. Weigh your portion raw when you can. If you can only weigh it cooked, round your serving size up.
The tool also leaves out allergies, sodium, and food safety for raw fish. It gives an estimate and not medical advice. When your state advisory is stricter than the calculator, follow the advisory.
Where the data comes from
The mercury values come from the FDA's monitoring data on mercury in commercial fish and shellfish, which covers samples taken from 1990 to 2012. The safety limit is the EPA's reference dose for methylmercury, set in 2001. Serving sizes for children follow FDA and EPA advice on eating fish. We list every source on the pages where we use it, and our about page explains how we check facts and fix mistakes.
Fish consumption calculator FAQ
How many fish meals are safe to eat per week?
It depends on your weight and the fish you pick. A 150-pound adult who eats 8-ounce meals can have about 9.5 meals of salmon, 1.7 meals of canned light tuna, or 0.6 meals of albacore each week. Those numbers cap mercury only. The FDA also suggests 2 to 3 servings of Best Choices fish a week, so treat the calculator as a ceiling and not a goal.
Is canned tuna safe to eat every week?
For most adults, yes. Canned light tuna averages 0.126 ppm, so a 150-pound adult can eat about 1.7 eight-ounce meals a week. Albacore averages 0.35 ppm, which is nearly three times higher. Plan on about half a meal of albacore. Pick each tuna in the calculator to see your own number.
Does cooking remove mercury from fish?
No. Mercury binds to muscle tissue, and heat does not break it down. Frying, baking, and grilling all leave it in place. You lower your intake only by choosing a fish with less mercury or by eating smaller servings.
What does the red, amber, or green gauge mean?
The gauge shows how many servings fit under your weekly mercury limit. Green means 2 or more servings. Amber means 1 to 2. Red means less than 1, so that fish should be a rare meal for you.
How much fish can kids eat?
Kids reach the mercury limit faster because they weigh less. The FDA suggests 2 servings a week of Best Choices fish. It lists 1 ounce at age 2, 2 ounces at ages 4 to 7, 3 ounces at ages 8 to 10, and 4 ounces from age 11. Tap the Child button to load a 40-pound child with a 2-ounce serving, then change the weight and serving to match your child. The age table below lists FDA serving sizes.
Can I use this calculator while pregnant or nursing?
Yes, but treat the result as a rough guide. The FDA advises 2 to 3 servings a week of Best Choices fish and says to skip swordfish, shark, and king mackerel. The calculator covers mercury only. Talk with your doctor before you change your diet.
Where do the mercury numbers come from?
They come from FDA monitoring data on mercury in commercial fish, paired with the EPA reference dose for methylmercury. Each value is an average. A single fish can run higher or lower, and fish from one lake can vary the most. The data sources section explains how we use them.
How do I check a fish I caught myself?
Start with your state fish advisory for that lake or river. If an agency or lab gave you a ppm value, pick "My own catch" in the calculator and type it in. Your state health or environment department posts the notice for each lake and river.
Does the calculator cover PCBs?
No. It measures mercury only. PCBs collect in fat and skin, so trimming and cooking methods matter more for them. Removing the skin and belly fat and cooking on a rack so fat drips away are the usual steps.
Is my weight or meal data saved anywhere?
No. The tool runs in your browser, and your numbers never go to a server. It remembers your last entries on your own device so you do not retype them, and the Reset button clears the form.
Fish safety basics to use with your result
The calculator gives you a mercury number. These FDA-based rules help you turn it into a weekly plan.
✅ Best choices
Salmon, shrimp, tilapia, catfish, cod, canned light tuna, and freshwater trout. The FDA says adults can eat 2 to 3 servings a week.
⚠️ Good choices
Halibut, canned albacore, and yellowfin tuna. The FDA suggests one serving a week.
⛔ Limit these
King mackerel, shark, and swordfish. Pregnant women and young children should avoid them.
Serving sizes for kids by age
The FDA suggests 2 servings a week of Best Choices fish for children. Use these sizes in the calculator to see the mercury math for your child.
| Age | Serving size |
|---|---|
| 2 to 3 years | 1 ounce |
| 4 to 7 years | 2 ounces |
| 8 to 10 years | 3 ounces |
| 11 years and older | 4 ounces |
If you are pregnant or nursing
The FDA advises 2 to 3 servings a week of Best Choices fish, or one serving of Good Choices fish. Skip king mackerel, shark, and swordfish. Tap the Pregnant / nursing button to load a 4-ounce serving, then check any fish you are unsure about. Your doctor has the final say.
If you eat tuna
Canned light tuna is a Best Choice at about 0.126 ppm. Albacore and yellowfin are Good Choices at about 0.35 ppm. A 150-pound adult can eat about 1.7 eight-ounce meals of light tuna a week, but only about 0.6 of albacore. Pick each one in the calculator to compare.
If you eat fish you catch
Start with the advisory for your lake or river. Your state health or environment department posts it. If you have a ppm value from an agency or lab, select My own catch and type it in.
Your next fish meal takes about ten seconds to check. Scroll back up to the calculator and try your numbers.