Daily magnesium
How much magnesium today?
Enter your age, what you ate, and a few habits. You get an estimate of the gap to the NIH target, and a supplement amount that stays under the upper limit.
- Targets from the NIH fact sheet
- Never above the 350 mg supplement cap
- No account. Answers stay in your browser
How the calculator works
Tell it about you
Age, sex, and pregnancy or lactation set the official daily target. Weight only helps size portions.
Describe what you ate
Write meals in plain words. Foods are matched to the NIH food table, then added up.
Get the gap and a safe dose
You see the gap to your target and, if needed, an elemental dose that stays under the upper limit.
How much magnesium do you need per day?
NIH recommended dietary allowance (RDA) for magnesium from food and supplements combined. * Values for infants are adequate intakes (AI).
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| 0–6 months | 30 mg* | 30 mg* | — | — |
| 7–12 months | 75 mg* | 75 mg* | — | — |
| 1–3 years | 80 mg | 80 mg | — | — |
| 4–8 years | 130 mg | 130 mg | — | — |
| 9–13 years | 240 mg | 240 mg | — | — |
| 14–18 years | 410 mg | 360 mg | 400 mg | 360 mg |
| 19–30 years | 400 mg | 310 mg | 350 mg | 310 mg |
| 31–50 years | 420 mg | 320 mg | 360 mg | 320 mg |
| 51+ years | 420 mg | 320 mg | — | — |
The upper limit for magnesium from supplements and medicines is 350 mg a day from age 9 (65 mg at 1–3 years, 110 mg at 4–8). Magnesium from food does not count toward that limit. NIH ODS · Magnesium needs by age and life stage
A daily magnesium estimate, tied to the NIH figures
howmuchmg compares one day of eating with the NIH recommended dietary allowance or adequate intake for your age and sex. For adults that is generally 400–420 mg a day for men and 310–320 mg for women. Pregnancy and lactation use the higher NIH figures for those years. Body weight does not change the official target. It only helps judge whether a portion was large or small.
The supplement number is elemental magnesium, the mineral itself, not the weight of the whole compound printed on the front of a bottle. From age 9 the NIH upper limit for magnesium from supplements and medicines is 350 mg a day. Food does not count toward that cap. The suggestion stays inside whatever room is left after what you already took. People who report kidney disease, and infants under one year, are not given a supplement dose.
If you have been eating this way for weeks or months, the page multiplies the daily gap by that time. The running total is missing intake, not a measurement of bone. A normal serum magnesium, about 0.75–0.95 mmol/L, does not prove that stores are full. Less than 1% of the body's magnesium is in blood, and an adult body holds about 25 g, with about half to 60% in bone.
What the result will and will not add
Glycinate is the default form because it is usually easier on the stomach. Citrate is the form if you want something that can also loosen stools. The page shows an approximate bottle weight for a product that is about 14% elemental as glycinate or about 16% as citrate, and it suggests splitting an elemental dose above 200 mg. Alcohol, smoking, a proton-pump inhibitor, or a loop or thiazide diuretic are explained beside the dose. They are not piled on top of the pill, and the page does not tell you to stop a prescribed medicine.
What magnesium does in the body
Magnesium is a cofactor in more than 300 enzyme systems. You need it to turn food into energy, to build protein, bone, and DNA, and to keep nerves and muscles, including the heart, working normally. It also helps regulate blood sugar and blood pressure.
An adult body holds about 25 grams of magnesium. Half to 60% of it sits in bone, and most of the rest is in muscle and soft tissue. Less than 1% is in the blood, which is why a routine blood test says little about your stores.
Magnesium supplement forms compared
The same dose of magnesium can come in very different amounts of powder. This table shows how much of each compound is elemental magnesium, and what the absorption research says.
| Form | Elemental magnesium | Absorption | Good to know |
|---|---|---|---|
| Magnesium glycinate | ≈14% | Few comparisons | Gentle on the stomach; a common everyday choice |
| Magnesium citrate | ≈16% | Better absorbed | Well absorbed; can loosen stools at higher doses |
| Magnesium malate | ≈15% | Few comparisons | Organic salt marketed for energy and muscles |
| Magnesium chloride | ≈12% | Better absorbed | Well absorbed by mouth; skin oils are not a measured dose |
| Magnesium lactate | ≈10–12% | Better absorbed | Well absorbed and usually gentle |
| Magnesium taurate | ≈9% | Few comparisons | Sold for the heart; little head-to-head data |
| Magnesium L-threonate | ≈7% | Few comparisons | Sold for memory; little magnesium per capsule |
| Magnesium orotate | ≈6–7% | Few comparisons | Expensive per milligram of magnesium |
| Magnesium oxide | ≈60% | Less absorbed | Lots of magnesium per tablet, much of it unabsorbed; laxative |
| Magnesium sulfate (Epsom salt) | ≈10% | Less absorbed | Laxative and bath salt, not a daily supplement |
| Magnesium carbonate | ≈29% | Few comparisons | Mostly used as an antacid |
Elemental share is by molecular weight; hydrated salts and blends vary, so trust the elemental number on the Supplement Facts panel. Absorption ratings follow the NIH fact sheet, which names citrate, lactate, aspartate, and chloride as better absorbed than oxide and sulfate. NIH ODS
Signs of low magnesium, and who is most at risk
Low intake rarely causes symptoms in healthy people at first, because the kidneys hold on to magnesium when intake drops. A shortfall that lasts months or years can show up in other ways.
Possible signs
- Loss of appetite, nausea, or vomiting
- Tiredness and weakness
- Numbness, tingling, and muscle cramps
- In severe deficiency: seizures, personality changes, and abnormal heart rhythms
People more likely to fall short
- People with digestive diseases such as Crohn's disease or celiac disease
- People with type 2 diabetes, who lose more magnesium in urine
- People with long-term alcohol dependence
- Older adults, who absorb less and lose more
- People on long-term proton-pump inhibitors or some diuretics
These signs have many causes. If you have them, see a clinician instead of starting a supplement on your own. Risk groups follow the NIH fact sheet.
A day of food that reaches the target
Most adults can reach their magnesium target with food. Here is one ordinary day, built from the same NIH food figures the calculator uses.
Breakfast
68 mg- oatmeal · 1 packet36
- banana · 1 medium32
Lunch
102 mg- black beans · 1/2 cup60
- brown rice · 1/2 cup42
Snack
122 mg- almonds · 1 ounce80
- yogurt · 8 ounces42
Dinner
147 mg- salmon · 3 ounces26
- spinach, boiled · 1/2 cup78
- baked potato with skin · 3.5 ounces43
Total: 439 mg
About 439 mg from food alone. That covers the adult target for women (310–320 mg) and for men (400–420 mg), and food never counts toward the 350 mg supplement limit.
Swap in foods you actually eat. Whole grains instead of refined ones, a handful of nuts or seeds, and beans a few times a week make the biggest difference.
Foods highest in magnesium
Milligrams per standard serving, from the same NIH table the calculator uses.
156mg
pumpkin seeds
1 ounce
111mg
chia seeds
1 ounce
80mg
almonds
1 ounce
78mg
spinach, boiled
1/2 cup
74mg
cashews
1 ounce
63mg
peanuts
1/4 cup
Read the form before you buy it
These guides stay inside the public sources: what each salt is, how absorption was compared, and how to read elemental magnesium on a label.
- Types of magnesium supplementsOxide, citrate, glycinate, malate, and more do not deliver the same magnesium. Elemental content, absorption, and side effects of each form compared.
- Magnesium glycinateMagnesium glycinate is a gentle, well-absorbed form that is about 14% elemental. What it is good for, how to dose it, and what the sleep claim rests on.
- Magnesium citrateMagnesium citrate is one of the better-absorbed forms and about 16% elemental. It can also loosen stools. How to dose it and when to choose another form.
- Glycinate vs citrateBoth are well absorbed. Citrate is more likely to loosen stools; glycinate is gentler for daily use. Elemental content, dosing, and how to choose.
- Magnesium for sleepMagnesium may help sleep when intake is low, but no form has been proven best. How much to take, when, and why glycinate is a sensible choice.
- Magnesium side effects and the 350 mg capToo much supplemental magnesium causes diarrhea, nausea, and cramps. The NIH upper limit by age, why food does not count, and who is at higher risk.
Questions about the daily target
How much magnesium do adults need in a day?
The NIH recommended dietary allowance is 400 mg for men 19–30 and 420 mg from age 31. For women it is 310 mg at 19–30 and 320 mg from age 31. Pregnancy and lactation are higher. These are totals from food and supplements together.
Does my weight change the target?
No. The official target follows age, sex, and pregnancy or lactation. Weight is only used when the meal text has to be turned into a portion.
What is elemental magnesium?
It is the magnesium mineral, not the weight of the whole salt. Magnesium glycinate is about 14% elemental and trimagnesium citrate about 16%. Magnesium oxide is about 60% elemental but is absorbed less completely. Use the elemental line on the Supplement Facts panel when the bottle prints one.
Can I take more than 350 mg from a supplement?
The NIH tolerable upper intake level for magnesium from supplements and medicines is 350 mg a day from age 9. The concern at higher doses is diarrhea from unabsorbed salts. Magnesium from food is not part of that limit. This site will not suggest a dose above the room left under the cap.
If my blood test is normal, am I fine?
A result inside about 0.75–0.95 mmol/L does not show that body stores are full. Blood holds less than 1% of the body's magnesium, and that level is kept up by drawing on bone and soft tissue. A low result is a late sign.
I have kidney disease. What should this page do?
It should not suggest a supplement. The kidneys clear extra magnesium. The page can still show food ideas. A dose belongs with the clinician who knows your labs.
What are the signs of magnesium deficiency?
Early signs are loss of appetite, nausea, vomiting, tiredness, and weakness. As a deficiency gets worse, numbness, tingling, muscle cramps, seizures, personality changes, and abnormal heart rhythms can appear. Healthy people rarely have symptoms from low intake alone.
Which form of magnesium is absorbed best?
Forms that dissolve well in liquid are absorbed more completely. The NIH names citrate, lactate, aspartate, and chloride as better absorbed than oxide and sulfate. Glycinate is popular and gentle, but has fewer head-to-head studies.
Can I get enough magnesium from food alone?
Usually, yes. Pumpkin seeds, chia, almonds, spinach, cashews, beans, and whole grains are rich sources. One ordinary day of oatmeal, beans with brown rice, almonds, yogurt, and salmon with spinach and potato gives about 440 mg.