Units ↔ mL ↔ mg
Syringe Units Converter
Convert between insulin syringe units, millilitres and milligrams. Enter the vial and water amounts to include mg and mcg in the conversion.
Syringe units converter
Example values are loaded. Replace them with the numbers on your own vial.
Needed only for mg and mcg.
Units to mL
On a U-100 insulin syringe, 100 units equal 1 mL, so:
10 units is 0.1 mL, 25 units is 0.25 mL, and 50 units is 0.5 mL. This part never depends on what is in the syringe.
Units to mg
Converting units to milligrams needs one more number: how concentrated the solution is. That comes from the vial: concentration (mg/mL) = peptide in vial (mg) ÷ water added (mL). Then:
Example: a 5 mg vial with 2 mL of water is 2.5 mg/mL. 20 units is 0.2 mL, which holds 0.2 × 2.5 = 0.5 mg (500 mcg).
A note on U-40 and other syringes
Some syringes, mostly for veterinary insulin, are U-40: 40 units per mL. A "unit" on those holds 2.5 times more liquid than on a U-100 syringe. Every conversion on this site assumes U-100. If you have a different syringe, work in mL. See how to read an insulin syringe.
Frequently asked questions
How many mL is 10 units?
10 units on a U-100 insulin syringe is 0.1 mL.
How many units is 0.25 mL?
0.25 mL is 25 units on a U-100 insulin syringe.
How do I convert units to mg?
Divide the units by 100 to get mL, then multiply by the concentration in mg/mL. The concentration is the mg in the vial divided by the mL of water you added.