Iron Dosage Calculator
Calculate your personalised iron dose based on Australian guidelines. NHMRC RDI: 8 mg/day (male) / 18 mg/day (female).
Calculate Your Dose
Important Warnings
- NEVER supplement iron without a blood test first — iron overload (haemochromatosis) is common in Australians.
- Keep iron supplements away from children — iron poisoning is a medical emergency.
- Common side effects: constipation, nausea, dark stools.
- Separate from zinc, calcium, tea, and coffee by 2+ hours.
Tips for Better Absorption
- Take with 100–200 mg vitamin C to increase absorption by up to 67%.
- Alternate-day dosing may be more effective than daily (emerging evidence).
- Iron bisglycinate is gentler on the stomach and can be taken with food.
- Retest ferritin after 3 months — don't supplement indefinitely.
Frequently Asked Questions
How do I know if I need iron supplements?
Get a blood test. Check ferritin (iron stores) and haemoglobin. Ferritin under 30 µg/L indicates low stores. Never supplement iron based on symptoms alone — excess iron is dangerous.
Why does iron cause constipation?
Iron supplements (especially ferrous sulfate) slow gut motility and can change stool consistency. Try iron bisglycinate (gentler on stomach), take alternate days, or increase fibre and water intake.
Can I take iron with food?
Iron bisglycinate can be taken with food without losing absorption. Ferrous sulfate absorbs best on an empty stomach, but take with food if it causes nausea. Always pair with vitamin C.
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This calculator provides general guidance based on Australian NHMRC guidelines and published clinical research. It is not medical advice. Individual needs vary. Always consult a healthcare professional before starting any supplement, especially if you are pregnant, breastfeeding, taking medications, or have a medical condition.