Magnesium Intake Calculator
Calculate recommended daily magnesium intake by age and sex.
Returns the NIH daily target in mg for men, women, teens, pregnant, and lactating adults.
How Magnesium Intake Is Calculated
Magnesium is involved in over 300 enzymatic reactions — including energy production, muscle function, and protein synthesis. Adequate intake depends on age, sex, and health status.
Recommended Dietary Allowances (RDA) for Magnesium:
| Group | RDA (mg/day) |
|---|---|
| Men 19–30 | 400 mg |
| Men 31+ | 420 mg |
| Women 19–30 | 310 mg |
| Women 31+ | 320 mg |
| Pregnant women | 350–360 mg |
| Breastfeeding women | 310–320 mg |
| Teens (14–18, male) | 410 mg |
| Teens (14–18, female) | 360 mg |
Upper Tolerable Limit: 350 mg/day from supplements (dietary magnesium has no upper limit — the body excretes excess). High-dose supplements can cause diarrhea, nausea, cramping.
Magnesium in Common Foods (mg per 100g):
- Pumpkin seeds: 592 mg
- Dark chocolate (70%+): 228 mg
- Almonds: 270 mg
- Spinach (cooked): 87 mg
- Black beans: 70 mg
- Avocado: 29 mg
- Banana: 27 mg
Worked Example: A 35-year-old woman (RDA = 320 mg/day):
- 30g almonds = 81 mg
- 100g spinach = 87 mg
- 100g black beans = 70 mg
- 1 medium banana = 33 mg
- Total: 271 mg: needs ~49 mg more from other foods or a small supplement
Deficiency Signs: muscle cramps, fatigue, irregular heartbeat, anxiety, poor sleep. Athletes and people under chronic stress have higher magnesium needs.