- mg → syringe units
units = mg ÷ (mg/mL) × 100Needs the concentration (vial mg ÷ water mL). - mcg → mg
mg = mcg ÷ 1,000Pure metric. No concentration needed. - units → mL
mL = units ÷ 100 (U-100)Depends on the syringe scale, not the peptide.
Which one do I need?
If you are converting between two mass units, use mcg to mg. If you are converting a syringe reading to a volume, use units to mL. That one depends only on the syringe, never on what's in it. If you are converting a mass to a syringe reading, use mg to units or the full peptide calculator. That one depends on how much water went into the vial.
Which conversions do people look up most?
Exact-value pages, each with a chart and a worked example: