Why Use This Tool?
Supplement and medication labels jump between mcg (micrograms) and mg (milligrams) — a 1,000-fold difference hidden in two letters. This converter makes the jump explicit: 1,000 mcg is exactly 1 mg, and the factor of a thousand is where dosing mistakes happen.
The gram row completes the ladder for context, showing how tiny these units are against everyday weights.
How It Works
- Enter the value from the label.
- Pick the unit it's expressed in (mcg, mg, or g).
- Read the equivalent in both other units — and double-check against the label.
Frequently Asked Questions
How do I convert mcg to mg?
Divide by 1,000 — 500 mcg is 0.5 mg, and 1,000 mcg is exactly 1 mg. The prefix micro- always means one-thousandth of milli-.
How do I convert mg to mcg?
Multiply by 1,000 — 0.5 mg is 500 mcg. The converter applies the factor precisely, which matters at these small scales.
Why do supplements use different units?
Potent substances (vitamin B12, vitamin D) are dosed in micrograms because effective amounts are tiny; less potent ones use milligrams. The unit hints at the potency.
Tips & Things to Watch
- mcg is also written µg — same unit, different symbol.
- The three-letter difference between mg and mcg is a classic labeling hazard.
- Verify doses with a pharmacist or doctor — this tool only converts units.