Micrograms (μg) to Milligrams (mg) Converter
Enter a value to instantly convert between weight units.
1 Microgram = 0.001 Milligram
Key Formulas
Kilogram → Pound
lb = kg × 2.20462Pound → Kilogram
kg = lb × 0.453592Gram → Ounce
oz = g × 0.035274Ounce → Gram
g = oz × 28.3495Formula
mg = μg ÷ 1000A microgram is one-thousandth of a milligram — the same relationship as millimeters to meters. Clinical labs, pharmaceutical manufacturers, and environmental testers work with both units: μg for trace substances (hormones, drugs, contaminants) and mg for larger amounts (supplement doses, reagents). Converting between them means dividing or multiplying by 1000.
Source: NIST SP 811, Table B.8
Frequently Asked Questions
Real-World Examples
A clinical lab finding 1000 μg of a compound per liter reports 1 mg/L for the medical record.
1000 μg = 1 mg
A thyroid test showing 500 μg of T4 per deciliter converts to 0.5 mg/dL for standard medical reporting.
500 μg = 0.5 mg
A vitamin D test result of 2500 μg/L (25 ng/mL) is 2.5 mg/L for the database.
2500 μg = 2.5 mg
A water quality test finding 100 μg/L of a contaminant reports 0.1 mg/L for EPA compliance.
100 μg = 0.1 mg