Units to mg calculator
The mark on the syringe, converted back into a dose. Units are volume, so the answer needs your vial strength and water volume; enter them and it is exact.
25 printable pages: dosing cards for the twelve most-used compounds at three water volumes, titration planners, a vial log, and five pages on what to do when it has already gone wrong.
How units become milligrams
The syringe only knows volume. Each unit on a U-100 insulin syringe is 0.01 mL, so 20 units is 0.2 mL whatever is in it. To turn that into a dose you multiply by the concentration, which is the milligrams in the vial divided by the water you added. 20 units of a 5 mg/mL solution (10 mg in 2 mL) is 0.2 mL times 5 mg/mL, which is 1 mg.
dose in mg = (units ÷ 100) × concentration in mg/mL. For micrograms, multiply the answer by 1,000.
Units to mg at the common concentrations
Find the mark you drew to on the left, then the column that matches your vial and water.
| Units drawn | Volume | 2.5 mg/mL | 5 mg/mL | 10 mg/mL | 15 mg/mL | 20 mg/mL |
|---|---|---|---|---|---|---|
| 5 units to mg | 0.05 mL | 0.125 mg | 0.25 mg | 0.5 mg | 0.75 mg | 1 mg |
| 10 units to mg | 0.1 mL | 0.25 mg | 0.5 mg | 1 mg | 1.5 mg | 2 mg |
| 12 units to mg | 0.12 mL | 0.3 mg | 0.6 mg | 1.2 mg | 1.8 mg | 2.4 mg |
| 15 units to mg | 0.15 mL | 0.375 mg | 0.75 mg | 1.5 mg | 2.25 mg | 3 mg |
| 20 units to mg | 0.2 mL | 0.5 mg | 1 mg | 2 mg | 3 mg | 4 mg |
| 25 units to mg | 0.25 mL | 0.625 mg | 1.25 mg | 2.5 mg | 3.75 mg | 5 mg |
| 30 units to mg | 0.3 mL | 0.75 mg | 1.5 mg | 3 mg | 4.5 mg | 6 mg |
| 35 units to mg | 0.35 mL | 0.875 mg | 1.75 mg | 3.5 mg | 5.25 mg | 7 mg |
| 40 units to mg | 0.4 mL | 1 mg | 2 mg | 4 mg | 6 mg | 8 mg |
| 50 units to mg | 0.5 mL | 1.25 mg | 2.5 mg | 5 mg | 7.5 mg | 10 mg |
| 60 units to mg | 0.6 mL | 1.5 mg | 3 mg | 6 mg | 9 mg | 12 mg |
| 70 units to mg | 0.7 mL | 1.75 mg | 3.5 mg | 7 mg | 10.5 mg | 14 mg |
| 80 units to mg | 0.8 mL | 2 mg | 4 mg | 8 mg | 12 mg | 16 mg |
| 100 units to mg | 1 mL | 2.5 mg | 5 mg | 10 mg | 15 mg | 20 mg |
2.5 mg/mL is a 5 mg vial in 2 mL; 5 mg/mL is 10 mg in 2 mL; 10 mg/mL is 10 mg in 1 mL, 20 mg in 2 mL or 30 mg in 3 mL; 15 mg/mL is 30 mg in 2 mL; 20 mg/mL is 20 mg in 1 mL or 60 mg in 3 mL. Any other setup: use the calculator above with your own numbers.
Units to mL
This part never changes. On a U-100 syringe: 5 units is 0.05 mL, 10 units is 0.1 mL, 20 units is 0.2 mL, 50 units is 0.5 mL and 100 units is 1 mL. On a U-40 syringe each unit is 0.025 mL, so 20 units is 0.5 mL; the syringe page explains how to tell them apart.
Common questions
- How many mg is 12 units?
- (12 divided by 100) times the concentration. At 5 mg/mL, 0.6 mg. At 10 mg/mL, 1.2 mg. At 2.5 mg/mL, 0.3 mg.
- How many mg is 35 units?
- At 5 mg/mL (10 mg in 2 mL), 1.75 mg. At 10 mg/mL, 3.5 mg. 35 units is 0.35 mL on a U-100 syringe, whatever the concentration.
- How many mg is 20 units?
- At 5 mg/mL, 1 mg. At 10 mg/mL, 2 mg. At 2.5 mg/mL, 0.5 mg. This is why "20 units" means nothing on its own; ask what the vial and water were.
- How many units is 0.5 mL?
- 50 units on a U-100 insulin syringe (100 units per mL). On a U-40 syringe, 20 units. Check the scale printed on your barrel before trusting either number.
Common conversions
The same three-step maths, pre-filled for the doses people ask about most. Units on a U-100 insulin syringe, where 100 units is 1 mL.
- mg to units calculator Any dose at any concentration, both directions, with the full reference tables
- Units to mg calculator (this page)
- 1 mg to units The most-asked conversion, at every common setup
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