Units to mL on a U-100 syringe
| Units | mL | Units | mL |
|---|---|---|---|
| 1 | 0.01 mL | 20 | 0.20 mL |
| 2 | 0.02 mL | 25 | 0.25 mL |
| 3 | 0.03 mL | 30 | 0.30 mL |
| 4 | 0.04 mL | 40 | 0.40 mL |
| 5 | 0.05 mL | 50 | 0.50 mL |
| 6 | 0.06 mL | 60 | 0.60 mL |
| 8 | 0.08 mL | 70 | 0.70 mL |
| 10 | 0.10 mL | 80 | 0.80 mL |
| 12 | 0.12 mL | 90 | 0.90 mL |
| 15 | 0.15 mL | 100 | 1.00 mL |
The three common sizes
| Syringe | Holds | Usual small lines | Numbers every | Best for |
|---|---|---|---|---|
| 0.3 mL | 30 units | 1 unit (often ½ unit) | 5 units | Small doses where precision matters |
| 0.5 mL | 50 units | 1 unit | 5 units | Doses up to 50 units |
| 1 mL | 100 units | 2 units | 10 units | Doses over 50 units |
Markings vary between brands, so always look at your own syringe. Read the dose at the edge of the black rubber plunger tip closest to the needle, with the syringe at eye level.
Turning units into a dose
Units tell you volume. To know how much substance a number of units holds, you need the concentration of your solution: dose = units ÷ 100 × concentration. With a 5 mg vial mixed in 2 mL (2,500 mcg/mL), 1 unit holds 25 mcg, so 10 units hold 250 mcg.
The units to mg calculator does this both ways for your own vial, and the reconstitution calculator draws the result on a picture of your syringe.
Syringe questions
How many mL is 1 unit on an insulin syringe?
On a U-100 insulin syringe, 1 unit is 0.01 mL, so 10 units is 0.1 mL and 100 units is 1 mL.
How many units are in a 1 mL syringe?
A 1 mL U-100 syringe holds 100 units. A 0.5 mL syringe holds 50 units and a 0.3 mL syringe holds 30 units.
What is the difference between U-100 and U-40 syringes?
They are marked for different insulin strengths. A U-100 syringe has 100 units per mL; a U-40 syringe has 40 units per mL, so the same number of units is a very different volume. The math on this site assumes U-100 syringes. Check the packaging.
Why does my 1 mL syringe only have marks every 2 units?
There is not enough room on a 1 mL barrel for a line at every unit, so most mark every 2 units with numbers every 10. For small doses, a 0.3 or 0.5 mL syringe is easier to read accurately.