Peptide reconstitution calculator: mg → syringe units
Math only, not medical advice. Enter your own numbers. We don't recommend compounds or doses, and we don't sell or link to any products.
Concentration = 5 mg ÷ 2 mL = 2.5 mg/mL Volume = 250 mcg ÷ 2500 mcg/mL = 0.1 mL Units = 0.1 mL × 100 (U-100) = 10 units
Math only, not medical advice. Verify every number yourself.
The formula
concentration (mg/mL) = vial mg ÷ water mL volume (mL) = amount mg ÷ concentration units = volume × 100 (U-100) | × 50 (U-50) | × 40 (U-40) one line (U-100): units = (amount_mcg × water_mL) ÷ (vial_mg × 10)
Example: 5 mg + 2 mL = 2.5 mg/mL. 250 mcg = 0.10 mL = 10 units on U-100, 5 on U-50, 4 on U-40.
FAQ
How many units is 250 mcg on an insulin syringe?
It depends on concentration. Example: a 5 mg vial with 2 mL of bacteriostatic water is 2,500 mcg/mL, so 250 mcg = 0.10 mL = 10 units on a U-100 syringe. With 1 mL of water the same 250 mcg is 5 units.
How do I convert mg to units on an insulin syringe?
Units measure volume, not mass. First find concentration (vial mg ÷ water mL). Then volume (mL) = dose mg ÷ concentration. Units = mL × 100 on U-100, × 50 on U-50, × 40 on U-40.
What is the difference between U-40 and U-100 syringes?
A U-100 syringe has 100 unit marks per mL (1 unit = 0.01 mL). A U-40 has 40 per mL (1 unit = 0.025 mL). Reading a U-100 number off a U-40 barrel gives 2.5× the intended volume.
How much bacteriostatic water should I add?
There is no single right volume. Water changes concentration, not the total amount in the vial. More water means a larger, easier-to-read draw for the same amount. Use reverse mode to pick the water volume that lands your amount on a chosen unit mark.
How many doses are in a vial?
Doses per vial = vial amount ÷ amount per draw (same units). A 5 mg vial at 250 mcg (0.25 mg) per draw holds 20 draws, regardless of how much water you added.