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Peptide unit converter
Set your solution's concentration, then convert in any direction between milligrams, micrograms, millilitres and insulin syringe units. Every field updates the others live. This is pure unit conversion — it assumes you already know your concentration, which you get from the vial mass and diluent volume.
Two kinds of conversion in one tool
It helps to know which conversions are fixed and which depend on your vial:
| Conversion | Depends on concentration? | Example |
|---|---|---|
| mg ↔ mcg | No — fixed | 1 mg = 1,000 mcg |
| mL ↔ syringe units | No — depends on the syringe | 0.1 mL = 10 units on U-100 |
| mass ↔ volume | Yes | 250 mcg = 0.1 mL only at 2,500 mcg/mL |
The third row is where errors live. Any conversion crossing between mass and volume requires the concentration, and a figure carried in your head is a figure you will misremember.
When to use this rather than the reconstitution calculator
- Use the reconstitution calculator when you are preparing a vial and need to derive the concentration from mass and diluent volume.
- Use this converter when the concentration is already known — a vial you set up last week, or a compounded GLP-1 vial whose concentration the pharmacy printed.
- Use the syringe unit converter when the question is specifically about barrel calibration.
Frequently asked questions
How many mcg are in 1 mg?
Exactly 1,000. The milligram-to-microgram conversion is a fixed metric relationship and has nothing to do with your solution's concentration.
How many mcg is 10 units on an insulin syringe?
It depends entirely on the concentration. Ten units is 0.1 mL on a U-100 syringe; how many micrograms that contains follows from your vial mass divided by the diluent volume you added. There is no universal answer.
What is the difference between IU and a syringe unit?
An International Unit is a measure of biological activity used for certain hormones and vitamins. A syringe unit is a volume marking. They share a word and nothing else, which is one of the more dangerous ambiguities in this field.
Related pages
Stop recalculating this every time
PepCycle stores each vial once — mass, diluent volume, concentration — and converts automatically for every entry after that, in both directions, including entries you backdate.
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