1 milligram (mg) = 1,000 micrograms (mcg). To convert mg to mcg, multiply by 1,000. To convert mcg to mg, divide by 1,000. Peptide vial labels typically use mg (e.g., 5 mg BPC-157), while the amounts you measure use mcg (e.g., 250 mcg per measurement). Use the converter below for instant results.
mg ↔ mcg
Peptide labels use both milligrams (mg) and micrograms (mcg). They measure the same thing at different scales. Type a number in either box and the other updates instantly.
The larger unit. Vial amounts are usually in mg
The smaller unit. Measurements are usually in mcg
1 milligram always equals 1,000 micrograms.
Quick reference
What's the difference between mg and mcg?
Both measure weight, just at different scales, like feet vs. inches.
- mg (milligram): one thousandth of a gram. Vial amounts are usually listed in mg (e.g., “5 mg vial”).
- mcg (microgram): one millionth of a gram, or one thousandth of a milligram. The amounts you measure are usually listed in mcg (e.g., “250 mcg per measurement”).
The rule is simple: 1 mg = 1,000 mcg. To go from mg to mcg, multiply by 1,000. To go from mcg to mg, divide by 1,000.
Why do labels use both?
Vial amounts use mg because the total amount of peptide is large enough that mg keeps the numbers simple (e.g., “5 mg” instead of “5,000 mcg”).
The amounts you measure use mcg because they are much smaller, and mcg avoids confusing decimals (e.g., “250 mcg” instead of “0.25 mg”).
This is why it can feel confusing, but once you know the conversion (multiply or divide by 1,000), it becomes second nature.
A real-world example
You have a 5 mg vial of BPC-157 and want to measure 250 mcg each time.
First, convert 250 mcg to mg: 250 ÷ 1,000 = 0.25 mg.
Now you can see how many measurements fit in the vial: 5 mg ÷ 0.25 mg = 20 measurements.
Our plan builder does all of this math for you automatically, including the syringe units and BAC water amount.
Related guides
Quick reference
| Milligrams (mg) | Micrograms (mcg) |
|---|---|
| 0.25 mg | 250 mcg |
| 0.5 mg | 500 mcg |
| 1 mg | 1,000 mcg |
| 2.5 mg | 2,500 mcg |
| 5 mg | 5,000 mcg |
| 10 mg | 10,000 mcg |
1 mg equals 1,000 mcg. Multiply mg by 1,000 to get mcg.
Related questions
How many mcg are in a mg?
There are 1,000 micrograms (mcg) in 1 milligram (mg). To convert mg to mcg, multiply by 1,000; to convert mcg to mg, divide by 1,000.
How many mcg is 0.25 mg?
0.25 mg is 250 mcg. Multiply 0.25 by 1,000 to convert milligrams to micrograms.
Why do vials use mg but measurements use mcg?
Vials are labeled by total content in milligrams (for example 5 mg), while the amounts you measure are small enough that micrograms (for example 250 mcg) state them more precisely.