MG to MCG Converter

How the conversion works

Milligrams and micrograms are both metric units of mass, separated by a factor of exactly one thousand — 1 mg = 1,000 mcg:

• mg → mcg: multiply by 1,000 — 0.5 mg × 1,000 = 500 mcg
• mcg → mg: divide by 1,000 — 250 mcg ÷ 1,000 = 0.25 mg

The microgram is written both as mcg and µg — they are the same unit. Labels often prefer "mcg" because a handwritten or badly printed µ can be mistaken for "m", turning a microgram into a milligram: a thousand-fold difference.

That difference is exactly why this conversion matters. It appears constantly on vitamin and supplement labels — vitamin D3 doses like 25 mcg (0.025 mg, sold as 1,000 IU), B12 at 500 or 1,000 mcg, melatonin anywhere from 0.3 to 5 mg — and on medication packaging, where thyroid and other drugs are dosed in micrograms.

A note on safety: this converter is informational, not medical advice. If you're converting a medication dose — especially between mg, mcg or IU — double-check the result with a pharmacist or the prescribing doctor before acting on it. A misplaced decimal in this unit pair is one of the most common dosage errors.

Quick reference table

How to use it

1. Type a value into either field — milligrams or micrograms.
2. The other side converts live; small decimals are preserved with up to six digits.
3. Tap a common value chip (0.025 to 5 mg) to start from a typical supplement dose.
4. Copy puts the full conversion (e.g. 0.025 mg = 25 mcg) on your clipboard.

When you need this

Comparing two vitamin D bottles where one lists 25 mcg and the other 0.025 mg. Reading a lab result in µg against a supplement label in mg. Checking that a B12 or folate dose matches what a doctor recommended. Filling in a health app that only accepts one of the two units. Anywhere small masses are written down, mg and mcg get mixed — and the thousand-fold gap makes precision worth a few seconds.

For everything beyond mass, the general Unit Converter covers length, volume, temperature and more. Kitchen and body weights live in the Ounces to Grams Converter, and food-energy labels in the Kilojoules to Calories Converter.

Private by design

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