How much magnesium per day? This free guide shows the recommended daily intake and safe supplement upper limit by age and sex — general reference information, not a treatment dose for deficiency.
Values follow widely used reference intakes (IOM/NIH) for healthy people. The upper limit is for magnesium from supplements, not from food and water.
General guidance for healthy people. Most magnesium should come from food (greens, nuts, seeds, wholegrains, legumes). If you have kidney disease or take medication, talk to a doctor before supplementing.
How the Magnesium Dosage Calculator Works
This tool restates commonly published reference intakes for magnesium by age, life stage, and sex, along with the safe upper limit for magnesium taken from supplements specifically. It’s a general reference lookup, not a personalized prescribing tool.
Formula: Recommended Daily Intake and Supplement Upper Limit are looked up from a reference table by age/life-stage group. For groups where sex matters (teens 14-18 and adults 19+), RDA = Female value if Sex = Female, otherwise Male value. Pregnant and breastfeeding groups use their own fixed value regardless of the sex toggle, and no supplement upper limit is set for infants under 1 year.
- Age / life stage — one of ten groups from infant (under 1 year) through adult 51+, pregnant, or breastfeeding; determines the base row in the reference table.
- Sex — male or female; only changes the result for teen (14-18) and adult (19+) groups, since other groups share one value.
Example Scenarios
| Age / Life Stage | Sex | Recommended Daily Intake | Supplement Upper Limit |
|---|---|---|---|
| Child (4-8 years) | N/A | 130 mg/day | 110 mg/day |
| Teen (14-18 years) | Male | 410 mg/day | 350 mg/day |
| Teen (14-18 years) | Female | 360 mg/day | 350 mg/day |
| Adult (19-30 years) | Female | 310 mg/day | 350 mg/day |
| Adult (31-50 years) | Male | 420 mg/day | 350 mg/day |
| Pregnant | N/A | 360 mg/day | 350 mg/day |
Magnesium Dosage Calculator FAQ
How much magnesium should I take per day?
It depends on your age, life stage, and sex. Reference intakes in this tool range from 75 mg/day for infants up to 420 mg/day for adult men ages 31 and over. Select your group to see your specific reference figure.Why does the recommended amount differ between men and women?
For teens and adults, reference intakes are typically set higher for males, reflecting average differences in body size. Other age groups (infants and younger children) use one shared value since the difference isn’t distinguished at those ages.What’s the difference between the RDA and the supplement upper limit for magnesium?
The recommended daily intake covers total magnesium from all sources, including food. The supplement upper limit (350 mg/day for most teens and adults in this tool) applies only to magnesium taken as a supplement, since magnesium from food doesn’t carry the same risk of digestive upset or toxicity.Is there an upper limit for magnesium for infants?
This tool doesn’t set a supplement upper limit for infants under 1 year, reflecting that supplemental magnesium generally isn’t recommended for infants without direct medical guidance — normal food and formula intake is considered the safe source.Can too much magnesium be dangerous?
Yes. High-dose magnesium, particularly from supplements, can cause digestive symptoms and more serious problems in people with kidney disease, since the kidneys are what clear excess magnesium from the body. Don’t exceed the upper limit shown without a doctor’s advice.Do pregnant or breastfeeding women need more magnesium?
This tool uses a separate fixed reference value for pregnancy (360 mg/day) and breastfeeding (320 mg/day), distinct from the standard adult female figures. Individual needs can still vary, so this is general information rather than personalized prenatal guidance.Related Calculators
Magnesium is often checked alongside other nutrients: see the vitamin D intake reference for another widely under-consumed nutrient, the daily sodium intake calculator if you’re tracking overall mineral balance, or the water intake calculator to round out your daily hydration and nutrient picture.