mcg to mg Converter
Created by: Isabelle Clarke
Last updated:
To convert micrograms to milligrams, divide by 1,000: 2,500 mcg is 2.5 mg and 200 mcg is 0.2 mg. To convert milligrams to micrograms, multiply by 1,000. One milligram is 1,000 micrograms, so mixing them up changes a dose a thousandfold. Check the unit on the label.
mcg to mg Converter
Conversion1 mcg = 0.001 mg. Switch direction to convert milligrams to micrograms.
mcg to mg conversion chart
mg = mcg ÷ 1,000.
| Micrograms (mcg) | Milligrams (mg) |
|---|---|
| 1 mcg | 0.001 mg |
| 2 mcg | 0.002 mg |
| 2.5 mcg | 0.0025 mg |
| 5 mcg | 0.005 mg |
| 10 mcg | 0.01 mg |
| 25 mcg | 0.025 mg |
| 50 mcg | 0.05 mg |
| 75 mcg | 0.075 mg |
| 100 mcg | 0.1 mg |
| 125 mcg | 0.125 mg |
| 150 mcg | 0.15 mg |
| 200 mcg | 0.2 mg |
| 250 mcg | 0.25 mg |
| 400 mcg | 0.4 mg |
| 500 mcg | 0.5 mg |
| 600 mcg | 0.6 mg |
| 800 mcg | 0.8 mg |
| 1,000 mcg | 1 mg |
| 1,500 mcg | 1.5 mg |
| 2,500 mcg | 2.5 mg |
| 5,000 mcg | 5 mg |
| 10,000 mcg | 10 mg |
| 18,000 mcg | 18 mg |
| Milligrams (mg) | Micrograms (mcg) |
|---|---|
| 0.01 mg | 10 mcg |
| 0.025 mg | 25 mcg |
| 0.05 mg | 50 mcg |
| 0.1 mg | 100 mcg |
| 0.125 mg | 125 mcg |
| 0.25 mg | 250 mcg |
| 0.5 mg | 500 mcg |
| 1 mg | 1,000 mcg |
| 2 mg | 2,000 mcg |
| 2.5 mg | 2,500 mcg |
| 5 mg | 5,000 mcg |
| 10 mg | 10,000 mcg |
How to convert micrograms to milligrams
mg = mcg ÷ 1,000
mcg = mg × 1,000
Worked examples
- Vitamin B12, 2,500 mcg: 2,500 ÷ 1,000 = 2.5 mg.
- Folic acid, 400 mcg: 400 ÷ 1,000 = 0.4 mg.
- Levothyroxine, 0.075 mg: 0.075 × 1,000 = 75 mcg.
Frequently Asked Questions
How do I convert mcg to mg?
Divide micrograms by 1,000. 2,500 mcg ÷ 1,000 = 2.5 mg, and 200 mcg = 0.2 mg. To go from mg to mcg, multiply by 1,000.
How many mcg are in 1 mg?
One milligram is 1,000 micrograms. A microgram is one millionth of a gram and a milligram is one thousandth, so a microgram is a thousand times smaller.
Is 1,000 mcg the same as 1 mg?
Yes. 1,000 mcg = 1 mg exactly. A vitamin B12 tablet labeled 1,000 mcg contains 1 mg of B12.
Is mcg the same as µg?
Yes. µg is the SI symbol for microgram. Medical labels use mcg instead because a handwritten µ can be misread as "m", which would make the dose a thousand times larger.
How many mg is 5,000 mcg of biotin?
5,000 mcg is 5 mg. Biotin supplements are often sold at 5,000 or 10,000 mcg (5 or 10 mg).
Why does mixing up mcg and mg matter?
The two units differ by a factor of 1,000, so confusing them with medicines such as levothyroxine (dosed in mcg) can cause a serious overdose or underdose. Always check the unit on the label or prescription.
Sources and References
- NIST: Metric (SI) prefixes. Micro means 10⁻⁶ and milli means 10⁻³.
- Institute for Safe Medication Practices: Error-prone abbreviations. Recommends writing mcg rather than µg.
For general information only. Check doses with a pharmacist or doctor.