Microgram (mcg) to Milligram (mg) Converter
Precise weight conversion for medicine doses, vitamin supplements, and scientific research—critical for accurate measurements where small values matter.
Result precision:
Enter microgram value (e.g., vitamin dose, drug amount)
Conversion formula: mg = mcg ÷ 1000
Quick Conversions (Common Values)
mcg to mg Conversion Tables
Micrograms to Milligrams
Common values for medicine and nutrition
| Micrograms (mcg) | ≈ | Milligrams (mg) |
|---|---|---|
| 1 mcg | ≈ | 0.001 mg |
| 50 mcg | ≈ | 0.050 mg |
| 100 mcg | ≈ | 0.100 mg |
| 250 mcg | ≈ | 0.250 mg |
| 500 mcg | ≈ | 0.500 mg |
| 750 mcg | ≈ | 0.750 mg |
| 1,000 mcg | ≈ | 1.000 mg |
| 5,000 mcg | ≈ | 5.000 mg |
Milligrams to Micrograms
Common values for prescriptions and supplements
| Milligrams (mg) | ≈ | Micrograms (mcg) |
|---|---|---|
| 0.001 mg | ≈ | 1 mcg |
| 0.050 mg | ≈ | 50 mcg |
| 0.100 mg | ≈ | 100 mcg |
| 0.250 mg | ≈ | 250 mcg |
| 0.500 mg | ≈ | 500 mcg |
| 1.000 mg | ≈ | 1,000 mcg |
| 2.500 mg | ≈ | 2,500 mcg |
| 5.000 mg | ≈ | 5,000 mcg |
About mcg & mg Units
Conversion Formulas
Micrograms to Milligrams
mg = mcg ÷ 1000
Example: 750 mcg ÷ 1000 = 0.75 mg
Milligrams to Micrograms
mcg = mg × 1000
Example: 0.25 mg × 1000 = 250 mcg
Unit Definitions
Microgram (mcg)
A unit of weight equal to one millionth of a gram (1 mcg = 0.000001 g). Used for small doses of medications (e.g., thyroid hormones) and trace nutrients (e.g., vitamin B12).
Milligram (mg)
A unit of weight equal to one thousandth of a gram (1 mg = 0.001 g). Common for most prescription drugs, over-the-counter medications, and vitamin supplements.
Common Use Cases
medicine Dosing
Converting prescription doses (e.g., 500 mcg levothyroxine = 0.5 mg) for accurate administration.
Nutrition
Reading food labels or supplement facts (e.g., 1.2 mg vitamin B6 = 1200 mcg).
Scientific Research
Measuring small quantities of chemicals or biological samples in laboratories.
Pediatric Care
Adjusting adult doses for children (e.g., 0.1 mg medication = 100 mcg) for safety.
Frequently Asked Questions
Precision is critical in medicine and nutrition because small errors can have significant consequences:
- A 100 mcg error (0.1 mg) could double a low-dose medication (e.g., thyroid drugs).
- Vitamin overdoses (e.g., vitamin A, D) often occur with mcg/mg confusion.
- Prescription labels may use either unit, requiring accurate conversion for safe use.
This converter defaults to 3 decimal places to minimize errors in critical contexts.
"µg" (mu-g) is the scientific symbol for micrograms, using the Greek letter "mu" (µ) to represent "micro-." However, "mcg" is often used on consumer products (medications, supplements) because:
- The "µ" symbol may not display correctly on all devices or printing systems.
- "mcg" is easier for non-scientific users to recognize and type.
- It reduces confusion with "mg" (milligrams) in handwritten notes.
Both "µg" and "mcg" are equivalent—1 µg = 1 mcg = 0.001 mg.
To convert mg to mcg, use the formula: mcg = mg × 1000
mcg = 0.2 × 1000 = 200 mcg
Always verify conversions with a pharmacist or healthcare provider when dealing with prescription medications.
The most dangerous mistake is mixing up multiplication and division:
- Accidental multiplication (instead of division) when converting mcg to mg: e.g., 500 mcg × 1000 = 500 mg (1000x too much).
- Accidental division (instead of multiplication) when converting mg to mcg: e.g., 1 mg ÷ 1000 = 0.001 mcg (1000x too little).
Always cross-check: if you’re going from a smaller unit (mcg) to a larger one (mg), the number should get smaller (divide).