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The tolerable upper intake level (UL), or upper limit, for calcium is 2,500 mg a day for adults 19 to 50. That is the most a day that is unlikely to cause harm for almost everyone; above it, the chance of side effects goes up. It is a ceiling, not a target. The limit counts calcium from food, water and supplements together. From age 51 it is 2,000 mg.
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Calcium upper limits by age
| Age | Males | Females | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| Birth to 6 months | 1,000 mg | 1,000 mg | – | – |
| 7-12 months | 1,500 mg | 1,500 mg | – | – |
| 1-3 years | 2,500 mg | 2,500 mg | – | – |
| 4-8 years | 2,500 mg | 2,500 mg | – | – |
| 9-13 years | 3,000 mg | 3,000 mg | – | – |
| 14-18 years | 3,000 mg | 3,000 mg | 3,000 mg | 3,000 mg |
| 19-30 years | 2,500 mg | 2,500 mg | 2,500 mg | 2,500 mg |
| 31-50 years | 2,500 mg | 2,500 mg | 2,500 mg | 2,500 mg |
| 51-70 years | 2,000 mg | 2,000 mg | – | – |
| 71+ years | 2,000 mg | 2,000 mg | – | – |
How much Calcium you need
| Age | Males | Females | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| Birth to 6 months | 200 mg* | 200 mg* | – | – |
| 7-12 months | 260 mg* | 260 mg* | – | – |
| 1-3 years | 700 mg | 700 mg | – | – |
| 4-8 years | 1,000 mg | 1,000 mg | – | – |
| 9-13 years | 1,300 mg | 1,300 mg | – | – |
| 14-18 years | 1,300 mg | 1,300 mg | 1,300 mg | 1,300 mg |
| 19-30 years | 1,000 mg | 1,000 mg | 1,000 mg | 1,000 mg |
| 31-50 years | 1,000 mg | 1,000 mg | 1,000 mg | 1,000 mg |
| 51-70 years | 1,000 mg | 1,200 mg | – | – |
| 71+ years | 1,200 mg | 1,200 mg | – | – |
* Adequate Intake (AI): the amount set when there isn’t enough evidence for an RDA.
What counts toward the Calcium limit
The limit counts calcium from food, water and supplements together.
Labels list elemental calcium in mg. That's the amount to add up, not the weight of the calcium compound (calcium carbonate is about 40% calcium, calcium citrate about 21%).
What happens with too much Calcium
The 2011 National Academies report (Ch. 6) says too much calcium can cause hypercalcemia and hypercalciuria, which "can cause renal insufficiency, vascular and soft tissue calcification," and kidney stones. The report used kidney stones as the indicator for the adult UL after the Women's Health Initiative trial, where the calcium and vitamin D doses "resulted in an increased risk (17 percent) of kidney stones". It also notes that calcium supplement intake "has long been associated with constipation."
Sources: Health Canada, Dietary Reference Intakes tables (the joint U.S.-Canada values); National Academies, Dietary Reference Intakes for Calcium and Vitamin D (2011); National Academies, Dietary Reference Intakes for Calcium and Vitamin D (2011). Limits checked November 8, 2026. More from the NIH: Office of Dietary Supplements Calcium fact sheet.
If you think you or a child took too much of a supplement, call Poison Control at 1-800-222-1222 (U.S., free, 24 hours) or use poison.org. In an emergency, call 911.
General information, not medical advice. Your doctor may recommend a different amount, for example to treat a deficiency. Talk to your doctor or pharmacist before you start, stop or change a supplement, especially if you are pregnant, nursing, take medication or have a medical condition.