Milligrams to Micrograms Converter
1 mg = 1,000 µg exactly. Type in either box.
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In medicine, write ‘microgram’ or ‘mcg’ rather than µg.
Multiply by a thousand
A milligram is a thousand micrograms.
1 mg = 1,000 µg exactly
The same safety note applies in this direction: in prescribing, micrograms should be written as "microgram" or "mcg", never as µg, because the Greek letter is too easily misread as an m.
The milligram
A thousandth of a gram. Most medicine doses are in milligrams: a standard paracetamol tablet is 500 mg, an aspirin 300 mg.
It is also the unit for nutrition label micronutrients — sodium, calcium, vitamin C.
The microgram
A millionth of a gram. It is the scale of vitamins, hormones and trace contaminants: a daily vitamin D dose is around 20 µg, and thyroid medication is prescribed in micrograms.
In medicine it is written out as "microgram" or "mcg" rather than µg, because a handwritten µ can be misread as an m — a thousand-fold dosing error.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where mass conversions come up
- Cooking, where recipes give grams in most of the world and ounces in the United States.
- Body weight, in kilograms nearly everywhere, pounds in America, and stones and pounds in Britain and Ireland.
- Shipping and postage, priced by weight bands that differ between carriers and countries.
- Medicine, where doses are in milligrams or micrograms and often scaled by body weight in kilograms.
- Precious metals, which use the troy ounce rather than the ordinary one.
The trap: which ounce, and which ton
Two units on this page have more than one meaning.
Ounces. The everyday avoirdupois ounce is 28.3495 grams. The troy ounce, used for gold, silver and platinum, is 31.1035 grams — about 10 % heavier. A gold price quoted per ounce always means troy. Using the wrong one on a bullion calculation is a ten per cent error.
Tons. A metric tonne is 1,000 kg. A US short ton is 2,000 lb, or 907 kg. A UK long ton is 2,240 lb, or 1,016 kg. The spread between the smallest and largest is over 12 %, which on a freight invoice is real money.
Mass is not weight
Strictly, everything on this page measures mass — how much matter there is. Weight is the force gravity exerts on that mass, and is properly measured in newtons.
Your mass is the same on the Moon; your weight is about a sixth. In everyday use nobody makes the distinction, and bathroom scales, baggage counters and recipes all use the two words interchangeably. It only matters in physics.
Numbers worth carrying
- 1 kg = 2.20462 lb, and 1 lb = 0.45359237 kg exactly.
- 1 oz = 28.3495 g. For cooking, 28 is close enough.
- 16 ounces to the pound, 14 pounds to the stone.
- Weigh, do not measure, for baking. A cup of flour varies by up to 20 % depending how it was packed; 120 g is 120 g.
Values people look up most
Each one opens the converter with the number already in it.
- 0.025 mg to µg
- 0.05 mg to µg
- 0.1 mg to µg
- 0.2 mg to µg
- 0.25 mg to µg
- 0.5 mg to µg
- 0.8 mg to µg
- 1 mg to µg
- 2 mg to µg
- 5 mg to µg
- 10 mg to µg
- 25 mg to µg
Quick reference
| Milligrams | Micrograms |
|---|---|
| 0.1 mg | 100 µg |
| 0.25 mg | 250 µg |
| 0.5 mg | 500 µg |
| 1 mg | 1,000 µg |
| 2 mg | 2,000 µg |
| 5 mg | 5,000 µg |
| 10 mg | 10,000 µg |
Questions people ask
How many micrograms in a milligram?
Exactly 1,000.
What is 0.5 mg in micrograms?
500 µg.
Should I write µg or mcg?
mcg in any medical context. The Greek letter is a known source of thousand-fold dosing errors.