How to convert insulin syringe units to mg

Divide the units by 100 to get mL (on a U-100 syringe), then multiply by the concentration in mg/mL. For example, 20 units at 5 mg/mL is 0.2 mL, which holds 1 mg. The same 20 units hold 2 mg at 10 mg/mL.

For research use only. Not medical advice. This page converts an amount; it does not recommend one.

mg held by U-100 units at common concentrations

Units (U-100)	Volume	2.5 mg/mL	3.33 mg/mL	5 mg/mL	7.5 mg/mL	10 mg/mL
5 units	0.05 mL	0.125 mg	0.167 mg	0.25 mg	0.375 mg	0.5 mg
10 units	0.1 mL	0.25 mg	0.333 mg	0.5 mg	0.75 mg	1 mg
20 units	0.2 mL	0.5 mg	0.667 mg	1 mg	1.5 mg	2 mg
25 units	0.25 mL	0.625 mg	0.833 mg	1.25 mg	1.875 mg	2.5 mg
50 units	0.5 mL	1.25 mg	1.667 mg	2.5 mg	3.75 mg	5 mg
100 units	1 mL	2.5 mg	3.333 mg	5 mg	7.5 mg	10 mg

Concentration is the mg in the vial divided by the mL of water added. Units measure volume: 100 units fill 1 mL on a U-100 syringe.

Convert another amount

Syringe type

Concentration

Peptide in vial (mg)Water added (mL)

Convert

Syringe units

Volume

0.5 mL

Amount

2.5 mg (2,500 mcg)

Per unit

50 mcg

At 5 mg/mL on a U-100 syringe.

0.5 mL

Draw 0.50 mL (≈ 50 units on a 0.5 mL syringe)

Common questions

Do insulin syringe units depend on the peptide?

No. Units are marks of volume: on a U-100 syringe, 100 units fill 1 mL. What changes between peptides is the concentration of the solution, which is the mg in the vial divided by the mL of water added.

What if my syringe is U-40?

A U-40 syringe has 40 marks per mL, so the same volume reads as 2.5 times fewer units. Read the scale printed on the syringe and use the matching column.