A multivitamin combines many vitamins and minerals in one pill. Enter what your label says to see how it adds up, and whether anything is too high or missing.
Calculator Official intake Study doses Best form Safety Sources
A multivitamin is checked nutrient by nutrient. Enter each amount from your label.
These are doses tested in research, not personal advice. Some exceed the upper limit because they were short courses or given under medical care.
No single dose
Physicians' Health Study II: 14,641 male doctors aged 50 and over took a daily multivitamin or placebo for about 11 years. Total cancer was 8% lower (17.0 against 18.3 cases per 1,000 person-years). No single cancer type and no cancer deaths were significantly reduced.
No single dose
COSMOS: 21,442 adults aged 60 and over took a daily multivitamin or placebo for a median of 3.6 years. There was no effect on total cancer, heart disease or deaths.
No single dose
Three COSMOS sub-studies found a small benefit for overall thinking and episodic memory with a daily multivitamin over 2 to 3 years, which the authors equate to about 2 years less cognitive ageing.
No best form
Why: Look for amounts close to the daily intake rather than mega-doses, B6 at or below 12 mg, no iron unless you need it, and iodine, vitamin D and B12 included.
A varied diet with vegetables, fruit, whole grains, dairy or alternatives, and protein foods covers most needs.
Check each nutrient against your other products: zinc, vitamin A, B6, iron and iodine add up fastest.
The US Preventive Services Task Force found the evidence insufficient to recommend multivitamins for preventing heart disease or cancer, and advises against beta-carotene and vitamin E supplements for that purpose.
Pregnant, breastfeeding, on medication, or managing a health condition? Check with a doctor or pharmacist before starting a supplement.
Values checked: November 12, 2026.
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