Daily Calcium Requirement Calculator

See how much calcium your bones need each day.

Result

1,200 mg
1.20 g
4.0x

How it is calculated

The result is a table lookup by age in years and sex, in mg per day. Under 1 year: 260 (an adequate-intake figure for infants). Ages 1 to 3: 700. Ages 4 to 8: 1000. Ages 9 to 18: 1300. Ages 19 to 50: 1000. Ages 51 to 70: 1200 for women and 1000 for men. Age 71 and over: 1200 for both. When sex is left empty, male is assumed, and the sex only matters in the 51 to 70 band. Grams are mg ÷ 1000, and the milk equivalent is mg ÷ 300, assuming about 300 mg of calcium per cup. An age at zero or above 120 gives no result. The values are US reference values; pregnancy, breastfeeding and national guidelines differ.

Worked example

A 55-year-old woman. Age 55 falls in the 51 to 70 band and the sex is female, so the requirement is 1,200 mg per day, or 1.20 g. The milk equivalent is 1200 ÷ 300 = 4.0x, about four cups of milk. A 55-year-old man in the same band gets 1,000 mg, which is 3.3 cups, so this is the age group where the two sexes differ.

Try this example →

Common mistakes

  • Leaving sex empty as a woman over 50. The default is male, so the tool returns 1,000 mg instead of 1,200 mg.
  • Reading the milk equivalent as a recommendation to drink that much milk. It is a conversion at 300 mg per cup; yogurt, cheese, tofu with calcium and fortified foods count too.
  • Comparing the number with a supplement label without checking the unit. The tool gives total calcium in mg per day from food and supplements together, not an amount to take as a pill.
  • Typing months for a baby. Age is in years, so use a fraction such as 0.5, which gives the infant value of 260 mg.
  • Applying the adult figure during pregnancy or breastfeeding, or with a medical condition. The tool has no separate values for them.

Sources

About this calculator

This calculator returns your Recommended Dietary Allowance (RDA) for calcium — the daily intake, in milligrams, expected to meet the needs of nearly all healthy people in a given age and sex group — based on reference values set by the National Institutes of Health Office of Dietary Supplements, derived from the Institute of Medicine's Dietary Reference Intakes.

The requirement shifts noticeably across the lifespan: teenagers aged 9-18 need a relatively high 1,300 mg/day during peak bone-building years, most adults aged 19-50 need 1,000 mg/day, and the requirement rises again to 1,200 mg/day for women 51+ and men 71+, reflecting the accelerated bone density loss that follows menopause and advanced age.

Dietitians, prenatal care providers, and anyone focused on bone health or osteoporosis prevention use this age-and-sex-specific RDA as the benchmark to check whether dietary calcium intake from foods like dairy, leafy greens, and fortified products, plus any supplements, is actually meeting daily needs.

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