🔬 MCG to MG Converter - Micrograms to Milligrams Calculator
Instantly convert micrograms (mcg/μg) to milligrams (mg) and vice versa! Essential for accurate medication dosages, vitamin supplements, and laboratory measurements. Includes conversion formulas, reference charts, and common dosage examples.
⚖️ MCG ⇄ MG Conversion Calculator
Example: 1000, 2500, 5000
Example: 1, 2.5, 5
📐 Conversion Formulas
MCG to MG Conversion
Or simply: Move the decimal point 3 places to the left
Example: 5,000 mcg ÷ 1,000 = 5 mg
MG to MCG Conversion
Or simply: Move the decimal point 3 places to the right
Example: 2.5 mg × 1,000 = 2,500 mcg
Metric Relationship
📊 Quick Reference Conversion Table
| Micrograms (mcg) | Milligrams (mg) | Common Use |
|---|---|---|
| 100 mcg | 0.1 mg | Vitamin K |
| 200 mcg | 0.2 mg | Biotin, Chromium |
| 400 mcg | 0.4 mg | Folic Acid (pregnancy) |
| 500 mcg | 0.5 mg | Vitamin B12 (low dose) |
| 1,000 mcg | 1 mg | Standard conversion |
| 2,000 mcg | 2 mg | Vitamin D (2,000 IU) |
| 2,500 mcg | 2.5 mg | Vitamin B12 (high dose) |
| 5,000 mcg | 5 mg | Biotin (hair/skin) |
| 10,000 mcg | 10 mg | Vitamin B12 (injection) |
💊 Common Medication Dosages (MCG vs MG)
| Medication/Supplement | Typical Dose (mcg) | Equivalent (mg) | Purpose |
|---|---|---|---|
| Levothyroxine | 25-200 mcg | 0.025-0.2 mg | Thyroid hormone |
| Vitamin B12 | 500-5,000 mcg | 0.5-5 mg | Energy, nerve health |
| Folic Acid | 400-800 mcg | 0.4-0.8 mg | Pregnancy, anemia |
| Vitamin D3 | 25-125 mcg | 0.025-0.125 mg | Bone health (1,000-5,000 IU) |
| Biotin | 30-10,000 mcg | 0.03-10 mg | Hair, skin, nails |
| Vitamin K | 90-120 mcg | 0.09-0.12 mg | Blood clotting |
| Selenium | 55-200 mcg | 0.055-0.2 mg | Antioxidant |
| Chromium | 200-1,000 mcg | 0.2-1 mg | Blood sugar support |
📝 Step-by-Step Conversion Guide
Method 1: Division Formula (MCG → MG)
- Identify your mcg value (e.g., 3,500 mcg)
- Divide by 1,000: 3,500 ÷ 1,000
- Result: 3.5 mg
Method 2: Decimal Point Shift (MCG → MG)
- Write your mcg value: 7,200 mcg
- Move decimal 3 places left: 7,200. → 7.200
- Result: 7.2 mg
Method 3: Multiplication Formula (MG → MCG)
- Identify your mg value (e.g., 0.5 mg)
- Multiply by 1,000: 0.5 × 1,000
- Result: 500 mcg
❓ Frequently Asked Questions
1 mg = 1,000 mcg. This is a fixed metric conversion. "Milli-" means one-thousandth, so 1 milligram is one-thousandth of a gram. "Micro-" means one-millionth, so 1 microgram is one-millionth of a gram. Therefore, 1,000 mcg = 1 mg.
Divide by 1,000 or move the decimal point 3 places to the left.
Formula: mg = mcg ÷ 1,000. Example: 4,000 mcg ÷ 1,000 = 4 mg.
Yes, exactly. 1000 mcg = 1 mg. This is standard metric conversion. Many vitamin labels show both units (e.g., "1000 mcg (1 mg) Vitamin B12").
MCG = microgram (μg), a metric unit equal to one-millionth of a gram (0.000001 g). Used in medications requiring very precise small doses: thyroid hormones, vitamins B12/D, folic acid, and potent drugs where accuracy is critical for safety.
Patient safety. Medication errors from incorrect conversions can cause:
- Overdosing: 1000× error (confusing mcg with mg) can be fatal
- Underdosing: Ineffective treatment
- Example: Prescribing 1 mg instead of 1 mcg of levothyroxine = 1000× overdose
Always double-check conversions, especially for pediatric, thyroid, and high-potency medications.
Top errors to avoid:
- ❌ Multiplying instead of dividing (mcg to mg)
- ❌ Confusing mcg (microgram) with mg (milligram)
- ❌ Moving decimal wrong direction
- ❌ Forgetting to convert when reading labels
- ✅ Always verify: Does my answer make sense? (mg should be smaller number than mcg)
🎯 Practical Examples
Example 1: Vitamin B12 Supplement
Label shows: 2,500 mcg
Convert to mg: 2,500 ÷ 1,000 = 2.5 mg
Why it matters: Understanding dosage in both units helps compare products.
Example 2: Thyroid Medication
Prescription: 125 mcg levothyroxine
Convert to mg: 125 ÷ 1,000 = 0.125 mg
Why it matters: Thyroid meds often labeled in mcg; pharmacies may show mg.
Example 3: Folic Acid for Pregnancy
Recommended: 400-800 mcg daily
Convert to mg: 400 ÷ 1,000 = 0.4 mg | 800 ÷ 1,000 = 0.8
mg
Why it matters: Prenatal vitamins show both units; ensure adequate intake.
⚠️ Important Medical Disclaimer
This calculator is for educational and reference purposes only.
- Always consult healthcare professionals for medication dosing
- Medication errors can be life-threatening
- Double-check all conversions with pharmacists
- Never adjust prescription doses without medical guidance
- When in doubt, verify with your doctor or pharmacist
📚 Official Resources & References
Authoritative Sources:
- NIST - International System of Units (SI) - Official metric standards
- BIPM - Bureau International des Poids et Mesures - Global measurement authority
- U.S. FDA - Food and Drug Administration medication standards
- ISMP - Institute for Safe Medication Practices - Medication safety
- NIH - Dietary Supplements - Vitamin and supplement information
- WHO - World Health Organization - International medication standards
🔄 Related Conversions
Explore more unit conversions on OmniCalculator.space:
- MG to G - Milligrams to Grams
- MCG to G - Micrograms to Grams
- Units to MCG/MG - Vitamin IU conversions
- Dosage Calculators - Weight-based medication dosing