Iron Supplement Supply Calculator
Estimate how long a bottle lasts, its daily and 30-day cost, elemental iron per day and the date it runs out.
Result
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Result
— days
- Cost per day
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- Cost per 30 days
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- Elemental iron per day
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- Runs out
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Safety: Iron overdose is dangerous, especially for children. Supplementation should follow a clinician's advice after a blood test.
Convert a salt weight to elemental iron
Supplement labels often state salt weight, not elemental iron. Use the fraction that matches the salt on the label.
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How the iron supply calculation works
When comparing over the counter iron supplements, the bottle size and price do not tell the whole story. Enter the number of pills, price, elemental iron per pill and pills taken per day to estimate supply and cost.
Supplement labels often state the salt weight, not the elemental iron. Typical elemental iron fractions are about 20% for ferrous sulfate, 12% for ferrous gluconate and 33% for ferrous fumarate. Comparing salt weight instead of elemental iron is a common way to compare bottles incorrectly.
The adult Tolerable Upper Intake Level is 45 mg of elemental iron per day. The comparison shown here is factual context only: iron overdose is dangerous, especially for children, and supplementation should follow a clinician's advice after a blood test.
days = pills per bottle ÷ pills per day; cost per day = price ÷ days; elemental iron per day = mg per pill × pills per day Iron supplement calculator FAQ
What does this calculator measure?
It estimates bottle duration, daily cost, 30-day cost, elemental iron per day and the date the bottle runs out from the values you enter.
What is elemental iron?
Elemental iron is the amount of iron supplied by the compound. Labels may show the heavier salt weight instead, so compare elemental iron when reviewing products.
Can this calculator tell me how much iron to take?
No. It does not recommend a dose or say that anyone needs iron. Supplementation should follow a clinician's advice after a blood test.
What does 45 mg mean here?
The calculator compares the entered daily elemental iron with the adult Tolerable Upper Intake Level of 45 mg per day. This is context, not dosing advice.
Are my values saved?
No. The calculation runs in your browser and this tool does not save the values you enter.