1 mL is equal to how many units in an insulin syringe?
1 mL is 100 units on a standard U-100 insulin syringe. The “U” number on insulin is its strength in units per mL: U-100 insulin has 100 units in every mL, and most insulin syringes are marked for it.[1] So a U-100 syringe reaches 100 units at exactly 1 mL.
| Scale | Units in 1 mL | Volume of 1 unit | Used for |
|---|---|---|---|
| U-100 | 100 | 0.01 mL | Standard insulin syringes |
| U-40 | 40 | 0.025 mL | Veterinary insulin |
| U-500 | 500 | 0.002 mL | U-500 insulin and its own syringe |
U-40 insulin for dogs and cats has 40 units per mL and is labelled for U-40 syringes only.[2] U-500 insulin has 500 units in each mL, and its label warns against any syringe other than the dedicated U-500 syringe.[3]
U-100 syringe, 1 mL · full = 100 units
U-40 syringe, 1 mL · full = 40 units
How many units in 1 mL of an insulin syringe, by syringe size
Only a 1 mL syringe actually holds a full 1 mL; smaller barrels hold a fraction of it. The common U-100 sizes are 1 mL (100 units), 0.5 mL (50 units) and 0.3 mL (30 units).[4] U-40 syringes come in 0.5 mL and 1 mL, and the dedicated U-500 syringe holds 0.5 mL.[6][5]
| Barrel | U-100 units | U-40 units | U-500 units |
|---|---|---|---|
| 0.3 mL | 30 | 12 | – |
| 0.5 mL | 50 | 20 | 250 (U-500 syringe) |
| 1 mL | 100 | 40 | – |
U-100 insulin syringe: 100 units equals 1 mL
Every line on a U-100 syringe is a fraction of a millilitre, which is why “100 units equals 1 mL” is printed knowledge for anyone measuring insulin. The arithmetic follows directly:
- 1 unit = 0.01 mL, so 5 units = 0.05 mL.
- 10 units = 0.1 mL and 25 units = 0.25 mL.
- 50 units = 0.5 mL, a full 0.5 mL syringe.
The line spacing varies: 1 mL syringes are made with 1-unit or 2-unit lines, so a full 1 mL barrel may show 100 or 50 small lines.[6]
Insulin units to mL
To turn insulin units into mL, divide by the insulin strength: units ÷ 100 for U-100, units ÷ 40 for U-40.
| Units | U-100 insulin (mL) | U-40 insulin (mL) |
|---|---|---|
| 1 units | 0.01 | 0.025 |
| 2 units | 0.02 | 0.05 |
| 5 units | 0.05 | 0.125 |
| 10 units | 0.1 | 0.25 |
| 15 units | 0.15 | 0.375 |
| 20 units | 0.2 | 0.5 |
| 25 units | 0.25 | 0.625 |
| 30 units | 0.3 | 0.75 |
| 40 units | 0.4 | 1 |
| 50 units | 0.5 | 1.25 |
| 75 units | 0.75 | 1.875 |
| 100 units | 1 | 2.5 |
The same number of units is a bigger volume of U-40 insulin, because it is weaker. That is why the scales must match: U-40 vs U-100 syringes shows what happens when they do not, and U-500 insulin syringe covers the five-times-stronger case.
Converting any volume
For any other volume, multiply by the scale: 0.35 mL is 35 units on U-100. The mL to units calculator does this for every scale, cc to units handles instructions written in cc, and for a dose in mg start from the mg to units calculator. Barrel sizes and markings are compared in insulin syringe sizes.
Frequently asked questions
How many units are in 1 mL?
100 units on a U-100 insulin syringe. 40 units on a U-40 syringe. U-500 insulin has 500 units per mL.
How many insulin units are in a mL?
It depends on the insulin strength: 100 units in a mL of U-100 insulin, 40 in U-40, 500 in U-500.
How many mL is 1 unit of insulin?
0.01 mL of U-100 insulin; 0.025 mL of U-40 insulin; 0.002 mL of U-500 insulin.
Is 100 units always 1 mL?
Only on the U-100 scale. 100 units of U-40 insulin would be 2.5 mL; 100 units of U-500 insulin is 0.2 mL.
Sources
- Giving an insulin injection
- Vetsulin (porcine insulin zinc suspension) label
- Humulin R U-500 (insulin human) prescribing information and instructions for use
- 7. Diabetes technology: Standards of Medical Care in Diabetes—2022
- BD receives FDA clearance for new syringe designed for the administration of Humulin R U-500 insulin
- Technical data sheet: insulin syringes (Micro-Fine, Ultra-Fine)