Insulin syringe units to mL

One rule covers this whole page: on a U-100 syringe, 100 units is 1 mL. So units ÷ 100 = mL, and mL × 100 = units. Everything below is that rule, written out.

10 units = 0.1 mL · 25 units = 0.25 mL · 50 units = 0.5 mL · 100 units = 1 mL. And backwards: 0.3 mL = 30 units, 0.5 mL = 50 units.

Units ↔ mLU-100 syringe

Units

Millilitres mL

—

Type in either box.

Units to mL

U-100 insulin syringe. "Syringe" is the smallest barrel that holds it — smaller barrels have finer marks.
Units	mL	Syringe	Marks on that barrel
1	0.01	30-unit	every 1 unit
2	0.02	30-unit	every 1 unit
3	0.03	30-unit	every 1 unit
4	0.04	30-unit	every 1 unit
5	0.05	30-unit	every 1 unit
6	0.06	30-unit	every 1 unit
8	0.08	30-unit	every 1 unit
10	0.1	30-unit	every 1 unit
12	0.12	30-unit	every 1 unit
15	0.15	30-unit	every 1 unit
20	0.2	30-unit	every 1 unit
25	0.25	30-unit	every 1 unit
30	0.3	30-unit	every 1 unit
35	0.35	50-unit	every 1 unit
40	0.4	50-unit	every 1 unit
45	0.45	50-unit	every 1 unit
50	0.5	50-unit	every 1 unit
60	0.6	100-unit	every 2 units
70	0.7	100-unit	every 2 units
75	0.75	100-unit	every 2 units — between marks
80	0.8	100-unit	every 2 units
90	0.9	100-unit	every 2 units
100	1	100-unit	every 2 units

mL to units

mL	Units	Fits in
0.05	5	30-unit syringe
0.1	10	30-unit syringe
0.15	15	30-unit syringe
0.2	20	30-unit syringe
0.25	25	30-unit syringe
0.3	30	30-unit syringe
0.4	40	50-unit syringe
0.5	50	50-unit syringe
0.6	60	100-unit syringe
0.75	75	100-unit syringe
0.8	80	100-unit syringe
1	100	100-unit syringe
1.5	150 ✗	no insulin syringe — 2 draws, or a 3 mL syringe marked in mL
2	200 ✗	no insulin syringe — 2 draws, or a 3 mL syringe marked in mL
3	300 ✗	no insulin syringe — 3 draws, or a 3 mL syringe marked in mL

What the common ones look like

5 units = 0.05 mL, on a 30-unit syringe

10 units = 0.1 mL, on a 30-unit syringe

25 units = 0.25 mL, on a 30-unit syringe

50 units = 0.5 mL, on a 50-unit syringe

100 units = 1 mL, on a 100-unit syringe

The one trap: U-40

Everything above assumes a U-100 syringe, which is what's sold for human insulin and what compounding pharmacies expect you to use. U-40 syringes exist — they're for pet insulin, they're cheaper, and they turn up in the same search results with the same photo.

Mark on barrel	U-100	U-40
10	0.1 mL	0.25 mL
20	0.2 mL	0.5 mL
40	0.4 mL	1 mL

The same number on the barrel is two and a half times as much liquid. It's printed on the syringe — U-100 or U-40. Look before you draw.

Which syringe: 30, 50 or 100 units

All three are U-100 — 100 units to the millilitre. The difference is how much of that millilitre the barrel holds and how fine the marks are. A 30-unit barrel holds 0.3 mL with a mark every unit; a 100-unit barrel holds 1 mL with a mark every 2. Same liquid, same conversion, easier reading on the small one. Use the smallest syringe your dose fits in; that's what "fit it for me" does on the calculator.

Questions this page gets asked

Is 100 units 1 mL?

On a U-100 syringe, yes, exactly. That's what "U-100" means: 100 units per mL.

How many units are in 1 mL?

100 on a U-100 syringe. 40 on a U-40. 50 on a U-50, which you're unlikely to meet. The number after the U is the answer.

Where is 10 units on an insulin syringe?

0.1 mL. On a 30-unit barrel that's a third of the way up; on a 100-unit barrel it's the first labelled mark after zero. Either way it's a small draw — readable, but slow down.

0.5 mL to units

50 units. Half a 100-unit barrel, or a full 50-unit syringe.

2 mL to units

200 units, which no insulin syringe holds. That's two full 100-unit draws, or a 3 mL syringe marked in millilitres — a different kind of syringe, and usually a different kind of injection.

Units to mg

Not possible from units alone. A unit is a volume; a milligram is an amount of drug; the link between them is the vial's concentration. That page does it, and the drug-specific versions are tirzepatide and semaglutide.

The calculator that starts from the vial rather than the syringe: how many units do I draw.