Reconstitution calculator
For powder you mix with bacteriostatic water: peptides, HCG and similar. Everything is worked out in your browser.
Concentration = powder ÷ water. Draw = dose ÷ concentration. On a U-100 insulin syringe, 1 mL is 100 units, so 0.1 mL is 10 units.
Example of the arithmetic: 5 mg with 2 mL of water is 2.5 mg/mL (2,500 mcg/mL), so 0.1 mL (the 10 mark) holds 250 mcg.
For planning only. IU can't be converted to mg without the product's own figure, so keep the powder and dose in the same kind of unit. Check with your doctor or pharmacist.
Questions
How do I work out the concentration after mixing?
Divide the amount of powder in the vial by the volume of water added. The result is the concentration, for example in mg/mL or mcg/mL. Adding more water makes each unit weaker and the volume you draw larger; adding less does the opposite.
How many units should I draw?
Divide the amount you've been prescribed by the concentration to get the volume in mL, then multiply by 100 for units on a U-100 insulin syringe. The calculator shows the draw on a picture of the syringe. Your prescriber or pharmacist sets the amount.
How much bacteriostatic water should I add?
There is no single right amount: the water only sets the concentration, not how much you take. For example, 2 mL in a 10 mg vial makes 5 mg/mL, and 1 mL makes 10 mg/mL. Follow the volume your prescriber or pharmacist gave you; if you have a choice, pick one that makes your prescribed amount an easy draw of more than 2 units.
Can I convert IU to mg?
Not without the product's own figure. IU measures biological activity and the conversion differs between products, so keep the powder and the amount per injection in the same kind of unit: both in IU, or both in mg or mcg.
Why does the calculator warn about small draws?
Under about 2 units, the marks on an insulin syringe are too close together to measure accurately. More water in the vial gives a bigger, easier draw for the same amount.
What are the mcg and mg units?
1 mg is 1,000 mcg (micrograms). Labels and prescriptions use either, so the calculator lets you pick the unit for the powder and for the amount per injection separately.