Calcium
Calcium is the most abundant mineral in the body, with about 99 percent stored in bones and teeth, where it provides structure and hardness. The remaining 1 percent is essential for muscle function, nerve transmission, blood clotting, and hormone secretion. Because the body cannot make calcium, needs must be met through diet, and requirements rise in adolescence and again in later life to protect bone.
The recommended intake sits at about 40% of the level considered the safe daily ceiling, leaving comfortable headroom.
Why it matters
What it does in your body
- Bone and teeth structure
- Muscle contraction
- Nerve signaling
- Blood clotting
- Hormone and enzyme secretion
- Vascular function
By age, sex, and life stage
How much you need
Values are RDAs except for infants, which are AI values. Needs rise to 1300 mg during the growth years of ages 9 to 18, drop to 1000 mg for most adults, then rise again: for women at age 51 and for men at age 71.
Recommended intake across life
in mg/dayBars scale to the highest recommendation shown. Where men and women differ, both values are listed.
Full reference table
| Life stage | Male | Female |
|---|---|---|
| Infants 0-6 mo | 200 (AI) | 200 (AI) |
| Infants 7-12 mo | 260 (AI) | 260 (AI) |
| Children 1-3 | 700 | 700 |
| Children 4-8 | 1000 | 1000 |
| Children 9-13 | 1300 | 1300 |
| Teens 14-18 | 1300 | 1300 |
| Adults 19-50 | 1000 | 1000 |
| Adults 51-70 | 1000 | 1200 |
| Adults 71+ | 1200 | 1200 |
| Pregnancy | n/a | 1000 to 1300 |
| Lactation | n/a | 1000 to 1300 |
Values in mg/day. AI marks an Adequate Intake, used when there is not enough evidence for a formal recommendation.
What moves the number
What changes your needs
Age
Needs peak at 1300 mg during ages 9 to 18 for bone building, then rise again after 50 as absorption efficiency declines and bone loss accelerates.
Sex
Women need 1200 mg starting at 51 because postmenopausal estrogen loss speeds bone resorption; men do not reach 1200 mg until 71.
Body weight / size
Larger skeletons hold more calcium, but the RDA is set per life stage rather than by body weight; adequacy also depends on vitamin D status, which governs absorption.
Pregnancy and lactation
The RDA does not increase because absorption efficiency rises and bone turnover adapts; pregnant and lactating teens still need 1300 mg and adults 1000 mg.
Running low
Signs you might not get enough
Most at risk: Postmenopausal women, people who avoid dairy (lactose intolerance, milk allergy, vegan diets), and individuals with limited diet variety are most likely to fall short.
Too much
Can you get too much?
Excess almost always comes from supplements, not food. Staying below the UL of 2000 to 2500 mg/day is advised because high supplemental intakes raise kidney stone risk and may have cardiovascular effects.
Where to get it
Best food sources
The bottom line
Aim for 1000 mg a day as an adult, rising to 1200 mg for women after 50 and men after 70. Dairy, fortified drinks, canned fish with bones, and leafy greens are safer than large supplement doses, and adequate vitamin D is needed to absorb what you eat.
Track calcium automatically
Calcium is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The recommended intakes, upper limits, and food-source amounts on this page come from the primary references below. Numbers were checked against the current NIH Office of Dietary Supplements fact sheets and the Institute of Medicine (now the National Academies) Dietary Reference Intakes.
- NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals
- Institute of Medicine (2011), Dietary Reference Intakes for Calcium and Vitamin D
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.