Peptide reconstitution calculator
Enter what's in the vial, how much bacteriostatic water you added, and the amount per draw. Get the concentration, volume, and exact insulin syringe units instantly.
Results
Math check: units = (amount per draw ÷ concentration) × units per mL. Always verify against your provider's instructions before acting on any number.
How it works
1. Concentration
Total amount in the vial ÷ mL of water = mcg per mL.
2. Volume
Amount per draw ÷ concentration = mL to draw.
3. Syringe units
mL × units per mL (100 for U-100) = the line on your syringe.
See the full math with worked examples →
Frequently asked questions
How do I convert mcg to units on an insulin syringe?
First find the concentration: total mcg in the vial divided by mL of water added. Divide the amount you need by that concentration to get mL, then multiply by 100 for a U-100 syringe. The calculator above does all three steps for you.
Does adding more water change how much is in the vial?
No. The total amount in the vial stays the same. More water lowers the concentration, so each unit on the syringe holds less, and you draw more units to reach the same amount.
What is the difference between mg and mcg?
1 mg equals 1,000 mcg. Mixing these up is the most common calculation error, so the calculator lets you choose the unit for each field and warns you when a number looks out of range.
What is the difference between U-100 and U-40 syringes?
A U-100 syringe has 100 unit markings per mL; a U-40 syringe has 40 per mL. The same volume reads as a different number of units, so always select the syringe you actually have.
Does this calculator tell me how much to use?
No. It only does arithmetic on the numbers you enter. Amounts and schedules should come from your licensed healthcare provider.