Vitamin D Dosage Calculator
Calculate your personalised vitamin d dose based on Australian guidelines. NHMRC RDI: 600 IU/day (male) / 600 IU/day (female).
Calculate Your Dose
Important Warnings
- Always get a blood test (25-hydroxyvitamin D) before high-dose supplementation.
- Co-supplement with vitamin K2 at doses above 2,000 IU to direct calcium to bones.
- People with kidney disease or sarcoidosis need medical supervision.
- Higher BMI may require higher doses.
Tips for Better Absorption
- Take with your fattiest meal for best absorption.
- 10–15 min of midday sun on arms/legs provides ~1,000 IU for light-skinned individuals.
- Southern Australians (Melbourne, Hobart, Adelaide) need more in winter.
- Dark-skinned individuals need 3–6x more sun exposure to produce the same vitamin D.
Frequently Asked Questions
How much vitamin D should Australians take?
Most Australian adults need 600–1,000 IU daily for maintenance, or 1,000–2,000 IU if deficient. Southern-state residents, shift workers, and those with darker skin need more. Get a blood test to know your level.
Should I take vitamin D in summer in Australia?
If you get regular sun exposure (10–15 min midday on arms/legs), you may produce enough in summer. But shift workers, office workers, and those who cover their skin should supplement year-round.
Can I take too much vitamin D?
Yes. The upper limit is 4,000 IU/day for adults. Excess can cause calcium buildup (hypercalcemia). Always test your blood levels before taking high doses.
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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.