Units to mg calculator: syringe units to mg in two steps
Divide the units by 100 to get mL, then multiply by the strength in mg/mL. Dividing by 100 works because 100 units on a U-100 syringe are 1 mL.[1]
mg = units ÷ 100 × strength (mg/mL)
Example. 20 units of a 10 mg/mL liquid: 20 ÷ 100 = 0.2 mL. 0.2 × 10 = 2 mg.
Units to mg chart: 5 to 100 units
Find the reading on the left and your strength across the top; each cell is the mg in the syringe.
| Reading | 1 mg/mL | 2 mg/mL | 5 mg/mL | 10 mg/mL | 20 mg/mL | 50 mg/mL |
|---|---|---|---|---|---|---|
| 5 units (0.05 mL) | 0.05 | 0.1 | 0.25 | 0.5 | 1 | 2.5 |
| 10 units (0.1 mL) | 0.1 | 0.2 | 0.5 | 1 | 2 | 5 |
| 12 units (0.12 mL) | 0.12 | 0.24 | 0.6 | 1.2 | 2.4 | 6 |
| 15 units (0.15 mL) | 0.15 | 0.3 | 0.75 | 1.5 | 3 | 7.5 |
| 20 units (0.2 mL) | 0.2 | 0.4 | 1 | 2 | 4 | 10 |
| 25 units (0.25 mL) | 0.25 | 0.5 | 1.25 | 2.5 | 5 | 12.5 |
| 30 units (0.3 mL) | 0.3 | 0.6 | 1.5 | 3 | 6 | 15 |
| 40 units (0.4 mL) | 0.4 | 0.8 | 2 | 4 | 8 | 20 |
| 50 units (0.5 mL) | 0.5 | 1 | 2.5 | 5 | 10 | 25 |
| 60 units (0.6 mL) | 0.6 | 1.2 | 3 | 6 | 12 | 30 |
| 100 units (1 mL) | 1 | 2 | 5 | 10 | 20 | 50 |
At 10 mg/mL, for example, 10 units is 1 mg, 20 units is 2 mg, 50 units is 5 mg and 100 units is 10 mg.
Worked units to mg examples
Three readings, worked out the same way: units ÷ 100 = mL, then mL × strength = mg.
| Reading | Strength | mL | mg |
|---|---|---|---|
| 35 units | 2.5 mg/mL | 0.35 | 0.875 |
| 8 units | 20 mg/mL | 0.08 | 1.6 |
| 30 units | 5 mg/mL | 0.3 | 1.5 |
| 75 units | 10 mg/mL | 0.75 | 7.5 |
20 units on a 0.3 mL syringe · 0.2 mL · 2 mg at 10 mg/mL
How much one unit holds
One unit holds the strength divided by 100: 0.1 mg at 10 mg/mL and 0.5 mg at 50 mg/mL. That is also the size of a one-unit reading error, so at 50 mg/mL misreading a single unit changes the dose by 0.5 mg. Check how many units one line is worth on your syringe: 1 mL barrels are made with 1-unit or 2-unit lines, and 0.3 mL barrels with 1-unit or ½-unit lines.[2]
Units are volume, not weight
Syringe units count insulin units only when the syringe holds U-100 insulin; with any other liquid, the lines are volume marks of 0.01 mL. The same 20 units hold 0.2 mg at 1 mg/mL and 4 mg at 20 mg/mL. That is why a dose in units means nothing without the strength.
Common units to mg mistakes
- Forgetting the strength. The same 20 units is 0.2 mg at 1 mg/mL and 4 mg at 20 mg/mL.
- Reading the wrong edge. Read at the thin black line of the plunger tip, not the end of the rod.
- Using a U-40 syringe. Its lines are 0.025 mL, not 0.01 mL; see U40 syringe.
Related conversions
Going the other way, from a dose in mg to the line to draw, is the mg to units calculator. If your label gives a total such as 50 mg in 5 mL, turn it into mg per mL first with the strength calculator. To see any reading in millilitres on U-100, U-40 or U-500 scales, use mL to units, and if you are unsure where to read the plunger, see how to read an insulin syringe.
How we checked these numbers
Every result on this page comes from the same code as the calculator, and the known answers below are run as tests before each release.
| Input | Expected | Basis |
|---|---|---|
| 20 units at 10 mg/mL | 2 mg | mg = units ÷ 100 × mg/mL |
| 35 units at 2.5 mg/mL | 0.875 mg | same |
| 0.4 mL at 5 mg/mL | 2 mg | mg = mL × mg/mL |
Known limits.
- Reads a U-100 scale. Does not convert insulin units to mg.
Download the data. Units to mg chart, 1–100 units × 1–100 mg/mL (CSV)
Change log.
- : Calculator, chart, worked examples and shareable links published.
Frequently asked questions
10 units to mg: how many mg is 10 units?
10 units on a U-100 syringe is 0.1 mL. Multiply by the strength: at 10 mg/mL it is 1 mg, at 5 mg/mL it is 0.5 mg, at 2 mg/mL it is 0.2 mg.
20 units to mg: how many mg is 20 units?
20 units is 0.2 mL. At 10 mg/mL that is 2 mg. At 5 mg/mL it is 1 mg. At 2.5 mg/mL it is 0.5 mg.
50 units to mg: how many mg is 50 units?
50 units is 0.5 mL. At 10 mg/mL that is 5 mg; at 2 mg/mL it is 1 mg.
Are syringe units the same as IU?
No. A syringe unit is a 0.01 mL volume line; an international unit (IU) measures biological activity. They coincide only for U-100 insulin in a U-100 syringe.
100 units to mg: how many mg is 100 units?
100 units is 1 mL, so it holds exactly the strength: 10 mg at 10 mg/mL. Insulin itself is dosed in units, not mg; this page does not convert insulin units to mg.