Quick answer

Most adults need 1,000 mg of calcium a day, and women from 51 and everyone from 71 need 1,200 mg, counting food and supplements together. Supplements are best absorbed in doses of 500 mg or less, so larger amounts are usually split. The upper limit is 2,000 to 2,500 mg a day.^1,2

Key facts

Counting food and supplements, US women average 1,009 mg of calcium a day and men 1,156 mg.²
Calcium antacids provide about 270 to 400 mg in each chewable tablet or soft chew.²
Two doses of 500 mg are absorbed better than a single 1,000 mg dose.¹
Nearly half of US children and teens aged 4 to 18 get less calcium than they need.²

Recommended amounts by age

Recommended calcium per day, from food and supplements^1,2
Age or stage	Male	Female
0 to 6 months	200 mg	200 mg
7 to 12 months	260 mg	260 mg
1 to 3 years	700 mg	700 mg
4 to 8 years	1,000 mg	1,000 mg
9 to 18 years	1,300 mg	1,300 mg
19 to 50 years	1,000 mg	1,000 mg
51 to 70 years	1,000 mg	1,200 mg
71 years and older	1,200 mg	1,200 mg
Pregnant or breastfeeding, 14 to 18		1,300 mg
Pregnant or breastfeeding, 19 and older		1,000 mg

For adults, these amounts were set at the intake needed to keep bone steady; for children and teens, at the intake that lets bone keep building. Pregnancy and breastfeeding do not raise the amount for adult women.²

Count your food first

Eight ounces of plain low-fat yogurt has about 415 mg of calcium, a cup of nonfat milk 299 mg, 3 ounces of canned sardines with bones 325 mg, and half a cup of firm tofu made with calcium sulfate 253 mg.²

The body absorbs about 30% of the calcium in dairy and fortified foods but only about 5% of the calcium in spinach, whose oxalic acid binds it. Calcium from broccoli, kale and cabbage is absorbed about as well as from milk, though they contain less per serving.²

A cup of nonfat milk and 8 ounces of plain yogurt together come to about 700 mg, so many people need a smaller supplement than they expect, or none. Add up a typical day before choosing a dose.²

How much to take at once

The share absorbed falls as the amount rises: about 45% of the calcium in a diet providing 200 mg a day, but 15% above 2,000 mg a day. From supplements, the body absorbs about 36% of a 300 mg dose and 28% of a 1,000 mg dose.²

That is why NIH advises taking 500 mg or less at a time. Someone who needs 1,000 mg a day from supplements absorbs more from two smaller doses, for example with breakfast and with dinner, than from one.¹

Reading the label

Multivitamins commonly contain about 200 to 300 mg of calcium. Calcium supplements, with or without vitamin D, commonly contain 500 or 600 mg.²

Labels list elemental calcium, the calcium itself. Calcium carbonate is 40% calcium and calcium citrate 21%, so a citrate product needs nearly twice the tablet weight, often more tablets, for the same amount.²

Amounts for older adults

Infants and young children absorb as much as 60% of the calcium they eat. Adults absorb about 25%, and the share keeps falling with age.²

From 71, men and women alike need 1,200 mg a day. Older adults more often have low stomach acid, which makes carbonate harder to absorb without food; citrate, or carbonate taken with meals, gets around that.^1,2

The upper limit

Upper limit for calcium per day, from food and supplements^1,2
Age or stage	Upper limit
0 to 6 months	1,000 mg
7 to 12 months	1,500 mg
1 to 8 years	2,500 mg
9 to 18 years, including pregnancy and breastfeeding	3,000 mg
19 to 50 years, including pregnancy and breastfeeding	2,500 mg
51 years and older	2,000 mg

The limits rest on a large trial in which women taking 1,000 mg of supplemental calcium a day for 7 years had more kidney stones, although later reviews of other trials did not find the link. Calcium from antacids counts toward the limit too.²

Questions people ask

Is 1,200 mg of calcium a day too much?

Not as a total from food and supplements: 1,200 mg is the recommended amount for women over 50 and everyone over 70, and it is below the 2,000 mg upper limit. Taken as a supplement on top of a diet that already provides 800 mg or more, it would push an adult over 50 past that limit.¹

Does calcium from antacids count?

Yes. Calcium carbonate antacids provide about 270 to 400 mg of calcium per tablet or chew, and it counts toward both your daily total and the upper limit.²

Do I need vitamin D with calcium?

Your body needs vitamin D to absorb calcium efficiently, and many supplements combine the two. In trials of adults over 50, adding vitamin D did not change the small gain in bone density that calcium produced.^2,3

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.