Check Your Magnesium Against the Recommended Amount
See how your intake compares with the recommended amount and the supplement limit.
This tool was built by Serge (MSc) using established science and government sources. My academic background covers plant biology, environmental biology, and biogeochemistry. My tools are for educational purposes and give practical guidance, not professional advice.
Magnesium has two numbers worth knowing: the recommended daily amount, and the upper limit for magnesium from supplements. This calculator compares your intake with both.
Pick your group, enter what you get from a supplement, and add a rough food figure if you know it. Use elemental magnesium, which the Elemental Mineral Calculator works out from the compound on the label.
Two numbers, two checks
Percentage of recommended = (supplement + food) ÷ recommended amount × 100
The recommended amounts are 400 to 420 mg a day for men and 310 to 320 mg for women, depending on age. The upper limit for magnesium from supplements is 350 mg a day, and it applies to supplements only, not to magnesium from food.
Reading the percentage
The percentage shows how close your total intake is to the recommended amount. The separate limit check matters because magnesium from supplements above 350 mg a day commonly causes diarrhoea and stomach upset in healthy adults.
Food magnesium does not carry that limit, because the body clears the excess. If your supplement figure alone is over 350 mg, the tool flags it.
Use the right number
Enter elemental magnesium, not the compound weight, or the result will be too high. To see how any single nutrient compares with its daily reference, use the Daily Value (%DV) Calculator, and if you take more than one product, the Upper Limit Checker adds them up.
Who should be careful
The 350 mg limit is for healthy adults. People with kidney problems can be at real risk at lower amounts and should speak with a doctor first.
This tool uses the standard adult figures only, so it is a general comparison with published reference values, not personal advice. For price, the Cost Per Dose Calculator shows what each real dose costs, and the Supplement Stack Builder lists what people commonly discuss for sleep.
Where this comes from
The recommended amounts come from the NIH Office of Dietary Supplements magnesium fact sheet.
The supplemental upper limit is listed in the Tolerable Upper Intake Levels for elements, published by the National Academies and hosted by the National Library of Medicine.
This calculator is for general education only and is not medical or professional advice. Speak with a qualified professional before making decisions about supplements, especially if you have a health condition or take medication.