How to Use This Calculator
Enter the dose and choose mcg or mg, then enter the concentration of your mixed vial and choose mcg/mL or mg/mL. Click Calculate to see the volume in mL and the units to draw on 0.3 mL, 0.5 mL and 1 mL U-100 syringes. Pick the syringe where the dose lands on a clear marking rather than between two lines.
mg, mL and Units: What Is the Difference?
Milligrams (mg) measure how much peptide you want. Millilitres (mL) measure how much liquid you draw. Units are the markings on an insulin syringe. On a U-100 syringe, every 100 units is 1 mL, so the units always equal the mL x 100, whatever the size of the barrel. The concentration of the vial links milligrams to millilitres, which is why the same dose can be 10 units from one vial and 20 units from another.
mg to Units Conversion Table (U-100 Syringe)
This table shows how many units a dose in mg is at common vial concentrations. It is only arithmetic. The Bac Water Calculator shows the concentration you get from a vial size and water volume. Values over 100 units do not fit in one 1 mL syringe.
| Dose | 1 mg/mL | 2 mg/mL | 2.5 mg/mL | 5 mg/mL | 10 mg/mL |
|---|---|---|---|---|---|
| 0.3 mg | 30 units | 15 units | 12 units | 6 units | 3 units |
| 1 mg | 100 units | 50 units | 40 units | 20 units | 10 units |
| 2.5 mg | 250 units | 125 units | 100 units | 50 units | 25 units |
| 5 mg | 500 units | 250 units | 200 units | 100 units | 50 units |
Choosing the Syringe Size
A smaller barrel spreads the same volume over more of its length, so small doses are easier to read. A 0.3 mL syringe holds up to 30 units, a 0.5 mL syringe up to 50 units and a 1 mL syringe up to 100 units. Pick the smallest syringe that holds your whole dose. If the dose does not fit any size well, change the amount of water in the vial with the Bac Water Calculator or compare options in the Peptide Reconstitution Volume Optimizer.
Who Should Use This
Researchers drawing doses from mixed vials who need to turn mg or mcg into units, and anyone checking a syringe calculation by hand.
What This Calculator Does
The Syringe Volume Calculator turns a dose in mcg or mg and a vial concentration into the volume to draw in mL and the matching units on 0.3 mL, 0.5 mL and 1 mL U-100 insulin syringes, so you can see which size gives the clearest reading.
Formula Used
Volume (mL) = Dose / Concentration (in the same units)Units = Volume (mL) x 100 (U-100 syringe)1 mg = 1,000 mcgExample Calculation
Limitations
This is a unit-conversion tool, not dosing guidance. It assumes a U-100 syringe, where 100 units equals 1 mL. U-40 syringes are marked differently, and using U-100 numbers on a U-40 syringe gives a 2.5 times error. Dead space and draw loss are not included.
Frequently Asked Questions
How many units is 1 mg?
It depends on the vial concentration. At 5 mg/mL, 1 mg is 20 units. At 2.5 mg/mL, it is 40 units. At 10 mg/mL, it is 10 units. All three are on a U-100 syringe.
How many mL is 10 units on an insulin syringe?
10 units is 0.1 mL on a U-100 syringe, because 100 units equals 1 mL.
How do I convert mcg to units?
Divide the dose in mcg by the concentration in mcg/mL to get mL, then multiply by 100. 250 mcg at 2,500 mcg/mL is 0.1 mL, which is 10 units.
Does the syringe size change the number of units?
No. On any U-100 syringe, units are always mL x 100. A smaller syringe only changes how much it holds and how far apart the markings are.
What happens if I use a U-40 syringe?
U-40 syringes hold 40 units per mL, not 100, so the markings mean something different. This calculator is for U-100 syringes only. Using its numbers on a U-40 syringe gives a 2.5 times error.
How many units is 1 mL, 2 mL or 3 mL of bac water in a syringe?
1 mL is 100 units on a U-100 syringe, 2 mL is 200 units and 3 mL is 300 units. A 1 mL syringe holds 100 units, so 2 mL and 3 mL are more than one syringe holds at once. These volumes are the water added to a vial, not a single draw.
How many mg is 10 units on a syringe?
It depends on the concentration of the vial. 10 units is 0.1 mL on a U-100 syringe, and mg = mL × concentration (mg/mL). At 5 mg/mL, 10 units is 0.5 mg. At 2.5 mg/mL, 10 units is 0.25 mg.
How do I convert mg to units on a syringe?
Divide the dose in mg by the concentration in mg/mL to get mL, then multiply by 100. For example, 2.5 mg at 5 mg/mL is 0.5 mL, or 50 units on a U-100 syringe.