Magnesium Intake Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/8/2026
The percentage of recommended magnesium intake is calculated with (magnesium consumed ÷ reference value) × 100. The ANSES reference value is 6 mg per kilogram of body weight per day; for a 70 kg person, that is 420 mg/day.
Explanation
Magnesium is involved in several hundred enzymatic reactions in the body, notably energy production, muscle contraction, and nerve transmission — a mild deficiency sometimes shows up as cramps or unusual fatigue, although these symptoms have many other possible causes. A distinctive feature of this mineral compared with other micronutrients covered on this site (like iron, whose reference value differs by sex): the ANSES reference intake for magnesium is calculated directly from body weight, at a rate of 6 mg per kilogram per day. For a 70 kg person, that is about 420 mg/day; for a 60 kg person, about 360 mg/day — the reference value therefore adapts individually to body size rather than relying on a single flat value per sex. The best dietary sources of magnesium include nuts (almonds, cashews), legumes, whole grains, spinach, and dark chocolate. A marked magnesium deficiency generally remains associated with particular situations (chronic alcoholism, certain digestive or kidney diseases, certain medications) rather than a typical Western diet, even though observed population intake often falls below the theoretical reference value. For another mineral involved in muscle contraction and heart rhythm, see our potassium intake calculator.
Example: 70 kg, 250 mg of magnesium consumed
Inputs
Magnesium consumed: 250 mg. Weight: 70 kg.
Calculation
Reference value = 70 × 6 = 420 mg/day. Percentage of target = (250 ÷ 420) × 100 ≈ 59.5%.
Result
This intake covers about 59.5% of the recommended magnesium intake for this profile.
Frequently asked questions
Why does the magnesium reference value depend on weight rather than being a fixed value?
Because magnesium needs are directly linked to the body mass that must be kept running (muscle mass in particular, where magnesium plays an important role in contraction). ANSES therefore expresses the reference value as a proportion of body weight (6 mg/kg/day) rather than a single flat amount, giving a more personalized benchmark than one fixed value for everyone.
Are muscle cramps always caused by a magnesium deficiency?
No, cramps have many possible causes (dehydration, muscle fatigue, poor circulation, certain medications, or simply a prolonged position), and the link with magnesium deficiency, although often mentioned, is not always scientifically confirmed for occasional cramps in an otherwise healthy person. Frequent or unexplained cramps warrant a healthcare professional's opinion rather than self-supplementation.
Can you take too much magnesium?
From diet alone, excess remains unlikely, as the body naturally regulates its absorption. However, high-dose supplementation can cause digestive issues (notably a laxative effect); ANSES sets a safety limit for supplements alone (excluding food and water), which should not be exceeded without medical advice in case of prolonged supplementation.