Syringe units chart
Units to mL for 0.3 mL, 0.5 mL and 1 mL U-100 insulin syringes, and how U-40 markings compare with U-100 for the same volume.
U-100 syringe sizes
| Syringe | Holds | Usually marked every | One marking |
|---|---|---|---|
| 0.3 mL | 30 units | 1 unit · some 0.5 unit | 0.01 mL |
| 0.5 mL | 50 units | 1 unit | 0.01 mL |
| 1 mL | 100 units | 2 units | 0.02 mL |
Markings vary by manufacturer. Count the lines between two printed numbers on your own syringe before relying on this table.
Units to mL charts
0.3 mL syringe
| Units | mL |
|---|---|
| 1 | 0.01 |
| 2 | 0.02 |
| 3 | 0.03 |
| 4 | 0.04 |
| 5 | 0.05 |
| 10 | 0.1 |
| 15 | 0.15 |
| 20 | 0.2 |
| 25 | 0.25 |
| 30 | 0.3 |
0.5 mL syringe
| Units | mL |
|---|---|
| 1 | 0.01 |
| 2 | 0.02 |
| 5 | 0.05 |
| 10 | 0.1 |
| 15 | 0.15 |
| 20 | 0.2 |
| 25 | 0.25 |
| 30 | 0.3 |
| 40 | 0.4 |
| 50 | 0.5 |
1 mL syringe
| Units | mL |
|---|---|
| 2 | 0.02 |
| 4 | 0.04 |
| 10 | 0.1 |
| 20 | 0.2 |
| 30 | 0.3 |
| 40 | 0.4 |
| 50 | 0.5 |
| 60 | 0.6 |
| 80 | 0.8 |
| 100 | 1 |
All three sizes use the same scale. Ten units is 0.1 mL on each of them. A smaller syringe has wider spacing between lines, which makes small volumes easier to read.
U-100 and U-40
The number after the U is how many units the syringe counts in 1 mL. A U-100 syringe is marked 100 units per mL, so one unit is 0.01 mL. A U-40 syringe is marked 40 units per mL, so one unit is 0.025 mL. U-100 is the standard scale for human insulin syringes. U-40 syringes are mostly sold for veterinary insulin.
The same number on the two syringes is a different volume. A U-40 unit is 2.5 times the volume of a U-100 unit. Every other calculator on this site assumes U-100, so if your syringe is U-40, convert the marking first.
Enter the marking you want to convert.
Arithmetic only. This tool does not recommend a dose or a schedule; use the ones your prescriber gave you.
| U-100 marking | Volume | U-40 marking |
|---|---|---|
| 5 units | 0.05 mL | 2 units |
| 10 units | 0.1 mL | 4 units |
| 20 units | 0.2 mL | 8 units |
| 25 units | 0.25 mL | 10 units |
| 50 units | 0.5 mL | 20 units |
| 75 units | 0.75 mL | 30 units |
| 100 units | 1 mL | 40 units |
Questions
How many mL is 10 units on an insulin syringe?
0.1 mL on a U-100 syringe. Divide the units by 100 to get mL.
Is 10 units the same on a 0.3 mL, 0.5 mL and 1 mL syringe?
Yes, as long as all three are U-100. The size of the syringe changes how much it holds and how far apart the lines are, not what a unit means.
How do I tell whether my syringe is U-100 or U-40?
It is printed on the barrel and on the packaging. In the United States U-100 syringes usually have an orange cap and U-40 syringes a red cap, but go by the printed scale, not the colour.
What is the difference between U-100 and U-40 markings?
A U-100 unit is 0.01 mL and a U-40 unit is 0.025 mL. A marking of 10 on a U-40 syringe is 0.25 mL, the same volume as 25 units on a U-100 syringe.
Do units tell me how many mg I am drawing?
No. Units are a volume. The mg in that volume depends on the concentration of your vial, which the reconstitution calculator works out.