MCG to MG Converter Dosage Chart
Micrograms (mcg or µg) and milligrams (mg) are two common units for measuring supplement and vitamin doses. 1 mg equals 1,000 mcg. This converter covers common supplement conversions including vitamin D (IU to mcg), vitamin B12, folate, iodine, and biotin.
MCG to MG Converter Dosage by Age Group
| Age Group | Age Range | Dose Range | Notes |
|---|---|---|---|
| Vitamin B12 — RDA adult | 18+ years | 2.4 mcg | 2.4 mcg = 0.0024 mg; most supplements overdose significantly |
| Vitamin B12 — common supplement | 18+ years | 500–1000 mcg | 500 mcg = 0.5 mg; 1,000 mcg = 1 mg |
| Folate — RDA adult | 18+ years | 400 mcg | 400 mcg DFE = 0.4 mg; in pregnancy: 600 mcg |
| Iodine — RDA adult | 18+ years | 150 mcg | 150 mcg = 0.15 mg |
| Biotin — common supplement | 18+ years | 1000–10000 mcg | 1,000 mcg = 1 mg; 10,000 mcg = 10 mg |
| Selenium — RDA adult | 18+ years | 55 mcg | 55 mcg = 0.055 mg; UL is 400 mcg |
MCG ↔ MG Converter
Convert micrograms (mcg / µg) to milligrams (mg) for vitamins and supplements. Divide mcg by 1,000 to get mg; multiply mg by 1,000 to get mcg.
Quick Reference: Common Supplement Values
| Supplement | Common label value | MCG equivalent | MG equivalent |
|---|---|---|---|
| Vitamin B12 | 1,000 mcg | 1,000 mcg | 1 mg |
| Folate / Folic Acid | 400 mcg DFE | 400 mcg | 0.4 mg |
| Iodine | 150 mcg | 150 mcg | 0.15 mg |
| Biotin | 5,000 mcg | 5,000 mcg | 5 mg |
| Selenium | 55 mcg | 55 mcg | 0.055 mg |
| Vitamin D3 | 1,000 IU = 25 mcg | 25 mcg | 0.025 mg |
| Vitamin K2 (MK-7) | 100 mcg | 100 mcg | 0.1 mg |
| Chromium | 200 mcg | 200 mcg | 0.2 mg |
Safety Cautions
- Confusion between mcg and mg is a common dosing error — always double-check the label unit.
- 1 mg = 1,000 mcg. A dose labeled as mg is 1,000× larger than the same number in mcg.
- Vitamin D is sometimes labeled in IU (International Units) rather than mcg: 1 mcg vitamin D = 40 IU.
- Folate and folic acid are measured in mcg DFE (Dietary Folate Equivalents) — 400 mcg DFE ≈ 240 mcg folic acid from supplements.
Frequently Asked Questions
How many mg is 1000 mcg?
1,000 mcg equals 1 mg. To convert mcg to mg, divide by 1,000. So 500 mcg = 0.5 mg, 2,000 mcg = 2 mg, and 10,000 mcg = 10 mg.
How many mcg is 1 mg?
1 mg equals 1,000 mcg. To convert mg to mcg, multiply by 1,000. So 0.5 mg = 500 mcg, 2 mg = 2,000 mcg, and 10 mg = 10,000 mcg.
What is 400 mcg of vitamin D in IU?
400 mcg of vitamin D equals 16,000 IU (400 × 40 = 16,000). This is an extremely high dose — typical vitamin D supplements are labeled 1,000–4,000 IU (25–100 mcg). Most supplements label vitamin D in IU, not mcg. If you see a supplement labeled '25 mcg vitamin D', that is equivalent to 1,000 IU.
What does mcg stand for?
MCG stands for microgram (µg). Micro- means one-millionth, so 1 mcg = 0.000001 grams = 0.001 mg. It is used for very potent substances (vitamin B12, iodine, folate, selenium) where milligram doses would be far too much.
Sources & References
- NIST International System of Units
- NIH ODS — Dietary Supplement Label Database