Calcium Dose: 1,000–1,200 mg a Day — How Much Calcium Per Day, and How Much of It to Supplement
Adults need 1,000 mg of calcium a day; women over 50 and everyone over 70 need 1,200 mg (NIH). That is your total from food and supplements together, not the size of your pill. U.S. women average 842 mg a day from food and men 1,083 mg, so many people need only a few hundred mg. Take 500 mg or less at a time: that is what absorbs best.
By Erin Rose Updated October 12, 2026 How we score
Which calcium to buy for your dose
Match the bottle to how you take it. The “Calcium” line on the label is the calcium itself, whatever the form.
- Check price on Amazon
You want citrate, the form you can take without food
Citracal Maximum Plus $0.22 a serving
650 mg of calcium in 2 caplets, plus zinc, copper and manganese. The label says two servings a day; take them at different times, since about 500 mg absorbs best at once. Not on a public testing list.
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You want a smaller citrate dose
21st Century Calcium Citrate + D3 Petites $0.11 a serving
400 mg in 2 small tablets, enough to close a typical food gap in one go. Not on a public testing list.
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You take calcium with meals
Nature Made Calcium 600 mg with D3 $0.10 a serving
600 mg of calcium carbonate a tablet, the cheapest calcium-only tablet on a testing list. Take it with food. On USP Verified.
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You also want magnesium and zinc
Nature Made Calcium, Magnesium and Zinc with D3 $0.05 a serving
333 mg of calcium with 133 mg of magnesium and 5 mg of zinc a tablet. On USP Verified.
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You want a small capsule
Thorne Calcium $0.23 a serving
250 mg of calcium a capsule, so you can take just what you need. It costs more per mg. On NSF/ANSI 173.
How much calcium a day, by age and sex
| Who | Calcium a day |
|---|---|
| Women 19 to 50 | 1,000 mg |
| Women 51 and over | 1,200 mg |
| Men 19 to 70 | 1,000 mg |
| Men 71 and over | 1,200 mg |
| Pregnancy and breastfeeding, 19 and over | 1,000 mg |
| Teens 14 to 18 | 1,300 mg |
| Upper limit, adults 19 to 50 | 2,500 mg |
| Upper limit, adults 51 and over | 2,000 mg |
Women need more after 50 “to lessen bone loss after menopause” (NIH). Pregnancy and breastfeeding do not raise the amount.
Food first: most people need only a top-up
In the U.S., women get about 842 mg of calcium a day from food and men about 1,083 mg (NIH). For a woman over 50, that leaves about 358 mg to reach 1,200 mg; for the average man under 70, food alone reaches 1,000 mg. Those are averages, so your own diet matters. Still, about 39% of people 4 and older fall below the average requirement, even counting supplements (NIH, 2007 to 2010 survey).
Dairy is the biggest source: one cup of milk has about 300 mg and 8 ounces of plain yogurt about 415 mg (NIH). Calcium-fortified soy milk and orange juice, tofu made with calcium, and canned fish with bones are good non-dairy sources. NIH says to meet your needs from food first and use supplements when you can’t.
How much calcium do you need to supplement?
Enter your usual servings of calcium-rich foods. We estimate your food calcium and show the gap to your target. These are our rough assumptions, not NIH figures: we count about 300 mg for each serving of dairy or fortified food, 100 mg for each plant serving, and 250 mg from the rest of your diet.
General guidance from NIH intake values, not medical advice.
Take 500 mg or less at a time
The more calcium you take at once, the smaller the share you absorb. NIH says absorption from supplements is highest with doses of 500 mg or less: the body absorbs about 36% of a 300 mg dose but only 28% of a 1,000 mg dose. The Bone Health and Osteoporosis Foundation puts the line at 500 to 600 mg. If you need more than that, split it: one dose with breakfast, one with dinner.
Carbonate is 40% calcium by weight and citrate 21%, but the label already lists the calcium itself (NIH). Take carbonate with a meal; citrate can be taken without food. Citrate vs carbonate.
What calcium labels tell you to take
We read 499 calcium labels from the NIH Dietary Supplement Label Database. 49% of them put more than 500 mg in one serving, more than absorbs best at once. Among calcium carbonate labels it was 78%. A 600 mg tablet is close to the line; two at once is not. Split them.
The scan is a sample of 499 of the 31,377 on-market calcium labels in the database; both figures held in both halves of the sample.
Calcium supplements and your heart
NIH calls the evidence mixed. In a 2010 review, people taking calcium supplements without vitamin D had about 27% to 31% more heart attacks (Bolland 2010). Other studies found no link, and an expert panel of bone and heart societies concluded that calcium within the upper limit is safe for the heart (NIH). NIH says more research is needed. The cautious step: take only the calcium your food leaves you short.
Kidney stones
In the Women’s Health Initiative, 36,282 women took 1,000 mg of calcium with vitamin D or a placebo for about 7 years. The calcium group had 17% more kidney stones than the placebo group (Jackson 2006). The U.S. Preventive Services Task Force agrees calcium with vitamin D raises kidney stones; two later reviews found no link (NIH). Taking calcium with food lowers the risk, according to the Bone Health and Osteoporosis Foundation.
Do calcium supplements prevent fractures?
Not clearly, for most people. In the best-run trials, calcium supplements had no effect on fractures, and they raised bone density by only 0.7% to 1.8% (Bolland 2015; Tai 2015). The U.S. Preventive Services Task Force advises against 1,000 mg or less of calcium with 400 IU or less of vitamin D to prevent fractures in healthy women past menopause who live at home; that advice does not cover people who already have osteoporosis or a past fracture. A Cochrane review found calcium with vitamin D cut hip fractures by about 16% in older adults, with the biggest gain in care homes (Avenell 2014). If you have osteoporosis, follow your doctor’s plan.
Vitamin D and K2
Vitamin D is needed to absorb calcium (NIH), which is why most calcium tablets add it. If you already take vitamin D, count it toward your total. How much vitamin D.
Vitamin K2 is often sold with calcium and D, but we found no evidence that the combination prevents fractures or heart problems. In the one trial that tested K2 with calcium and vitamin D, adding calcium and D brought no extra benefit (Zhang 2020). Reviews of K2 alone found fewer fractures only after leaving out one study, mostly in people with osteoporosis. More on K2.
Calcium after 50 and after 70
Women need 1,200 mg a day from 51 on, and men from 71 on (NIH). The upper limit drops to 2,000 mg after 50. On average, women lose about 1% of their bone density a year after menopause, and about 30% of women past menopause in the U.S. and Europe have osteoporosis (NIH). Older adults with low stomach acid may do better with citrate: NIH says carbonate appears to cause more gas, bloating and constipation, especially in them. If you are being treated for osteoporosis, your doctor will set your calcium.
How to take it, and medicines to watch
- With a meal. All calcium supplements absorb better with food, and carbonate needs it (NIH).
- Split doses over 500 mg. One in the morning, one in the evening.
- Thyroid medicine. Take levothyroxine at least 4 hours apart from calcium carbonate (NIH).
- Antibiotics. Take quinolone antibiotics (such as ciprofloxacin) 2 hours before or after calcium (NIH).
- Other medicines. Dolutegravir (an HIV medicine) should be taken 2 hours before or 6 hours after calcium, and lithium with calcium may raise blood calcium (NIH). Ask your pharmacist about yours.
Questions
How much calcium should I take a day?
Your target is 1,000 mg a day, or 1,200 mg if you are a woman over 50 or anyone over 70, counting food and supplements together (NIH). Take only the gap your food leaves. U.S. women average 842 mg a day from food and men 1,083 mg.
How much calcium can your body absorb at once?
Absorption from supplements is highest at 500 mg or less at a time (NIH); the Bone Health and Osteoporosis Foundation says 500 to 600 mg. Split a larger amount into two doses.
Do calcium supplements cause heart attacks?
The evidence is mixed (NIH). Some studies found calcium supplements might raise heart disease risk, and one 2010 review found more heart attacks (Bolland 2010); others, and an expert panel, found no link. Taking only the calcium your food leaves you short is the cautious choice.
Do calcium supplements cause kidney stones?
They might. In the largest trial, calcium with vitamin D raised the risk of kidney stones by 17% (Jackson 2006), and the U.S. task force agrees. Two later reviews found no link (NIH). Taking calcium with food lowers the risk, according to the Bone Health and Osteoporosis Foundation.
How long after thyroid medicine can I take calcium?
Take levothyroxine at least 4 hours apart from calcium carbonate (NIH). Ask your pharmacist about your own medicines.
Do I need vitamin K2 with calcium?
No study we read shows that adding K2 to calcium and vitamin D prevents fractures or heart problems. In the one trial that gave K2 with and without calcium and D, the calcium and D added nothing to K2’s effect on bone (Zhang 2020).
Sources
- NIH Office of Dietary Supplements. Calcium fact sheet for health professionals (updated June 22, 2026; read October 12, 2026). RDA (Table 1), upper limit (Table 3), food (Table 2), intakes, absorption, forms, heart, kidney stones, medicines.
- Bone Health and Osteoporosis Foundation. Calcium and vitamin D supplement safety fact sheet (read October 12, 2026).
- Bolland MJ, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010. PubMed 20671013
- Jackson RD, et al. Calcium plus vitamin D supplementation and the risk of fractures. N Engl J Med. 2006. PubMed 16481635
- Bolland MJ, et al. Calcium intake and risk of fracture: systematic review. BMJ. 2015. PubMed 26420387. Tai V, et al. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. 2015. PubMed 26420598
- US Preventive Services Task Force. Vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling adults: recommendation statement. JAMA. 2018. PubMed 29677309
- Avenell A, et al. Vitamin D and vitamin D analogues for preventing fractures in post-menopausal women and older men. Cochrane Database Syst Rev. 2014. PubMed 24729336
- Zhang Y, et al. Effect of low-dose vitamin K2 supplementation on bone mineral density in middle-aged and elderly Chinese: a randomized controlled study. Calcif Tissue Int. 2020. PubMed 32060566
- NIH Dietary Supplement Label Database, a sample of 499 calcium labels; our analysis. Product labels: the database or each brand’s page. Testing lists: NSF/ANSI 173 and NSF Certified for Sport (our copies); USP Verified (our copy of September 22, 2026).