Tool
Vitamin D dose calculator
Enter your last 25(OH)D blood test and this tool tells you where you stand and the daily vitamin D3 dose to reach a healthy level — then when to retest. It uses the evidence-based dose-response of ~4–7 ng/mL per 1,000 IU/day, not the inflated “10 ng/mL per 1,000 IU” rule of thumb.
Unit
Enter your number above to see where you stand and the dose to get to target.
Estimate only — response varies with baseline, body weight, and absorption. The number you retest is what counts. For the full picture — what raising your level actually does, the optimal-target debate, and the trial evidence — see the Vitamin D guide.