400 IU to mcg
Instant conversion with safety verification based on WHO/NIH standards.
400 IU=10 mcg
Based on Vitamin D3 (1 IU = 0.025 mcg)
Within the Tolerable Upper Intake Level (UL) of 100 mcg/day.
Conversion for All Applicable Substances
| Substance | 400 IU = | Factor | Safety |
|---|---|---|---|
| Vitamin D3 (Cholecalciferol)Primary | 10 mcg | 1 IU = 0.025 mcg | ✓ Safe |
| Vitamin A (Retinol) | 120 mcg | 1 IU = 0.3 mcg | ✓ Safe |
| Vitamin A (Beta-Carotene) | 20 mcg | 1 IU = 0.05 mcg | ✓ Safe |
How We Calculate
The conversion between International Units (IU) and weight units (mcg) depends on the specific substance. Each substance has a unique conversion factor defined by international pharmacological standards (WHO/NIH).
Step-by-step for Vitamin D3
- Identify the conversion factor: For Vitamin D3, 1 IU = 0.025 mcg.
- Multiply: 400 IU × 0.025 = 10 mcg
- Verify safety: Within the Tolerable Upper Intake Level (UL) of 100 mcg/day.
400 IU × 0.025 = 10 mcg
Quick Reference Table
Common IU to mcg conversions for Vitamin D3. The current value is highlighted.
Related Conversions
Conversion factors sourced from NIH Office of Dietary Supplements, WHO 2026. Always consult a healthcare professional before making dosage decisions.