Free syringe conversion toolUpdated 24 September 2026

Insulin syringe unit converter.

On a U-100 syringe, 100 units is 1 mL, so 1 unit is 0.01 mL. Converting a dose in mg or mcg to units needs the vial's concentration. The converter does both, in either direction.

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How to read a U-100 syringe.

A U-100 barrel is a fixed ruler: 100 marks to the millilitre, whatever is inside it.

01
Check the barrel scale
Confirm that the syringe is U-100
02
Convert units and mL
One unit equals 0.01 mL
03
Add the concentration
Only needed to convert micrograms

Units to millilitres

This conversion is fixed and needs nothing else. A U-100 syringe is graduated at 100 units per millilitre, so every unit is one hundredth of a millilitre, regardless of what the syringe contains. Half a unit, marked on some 0.3 mL barrels, is 0.005 mL. On a U-40 barrel each unit is 0.025 mL.

Insulin syringe units to millilitres on U-100 and U-40 scales. 1 mL is the largest common insulin syringe.

Units	U-100 (mL)	U-40 (mL)
1 unit	0.01 mL	0.025 mL
2 units	0.02 mL	0.05 mL
5 units	0.05 mL	0.125 mL
10 units	0.10 mL	0.25 mL
15 units	0.15 mL	0.375 mL
20 units	0.20 mL	0.50 mL
25 units	0.25 mL	0.625 mL
30 units	0.30 mL	0.75 mL
40 units	0.40 mL	1.00 mL
50 units	0.50 mL	Over 1 mL
60 units	0.60 mL	Over 1 mL
80 units	0.80 mL	Over 1 mL
100 units	1.00 mL	Over 1 mL

Millilitres to units

Going the other way, multiply the millilitres by 100 to get U-100 units. 0.1 mL is 10 units, and 0.25 mL is 25 units.

Millilitres to units on a U-100 insulin syringe.

Millilitres (mL)	U-100 units
0.01 mL	1 unit
0.05 mL	5 units
0.1 mL	10 units
0.15 mL	15 units
0.2 mL	20 units
0.25 mL	25 units
0.3 mL	30 units
0.4 mL	40 units
0.5 mL	50 units
0.75 mL	75 units
1 mL	100 units

The three common barrel sizes

All three are U-100, and the scale is identical. What differs is how much of it is printed on the barrel, and therefore how finely it is graduated. How to read a U-100 syringe walks through the markings line by line.

Barrel	Total capacity	Typical graduation	Reads well for
0.3 mL	30 units	1 unit, often ½ unit	Small draws
0.5 mL	50 units	1 unit	Mid-range draws
1 mL	100 units	2 units	Larger draws

Micrograms to units

This conversion is not fixed, because micrograms measure peptide and units measure volume. The bridge between them is the concentration of the reconstituted vial, which is set by the vial strength and how much bacteriostatic water went in. The calculator above does all three steps, and the peptide dosage calculator starts from a dose written in mg as well as mcg.

Convert the dose to mg: mcg ÷ 1,000.
Convert to volume: mg ÷ concentration in mg/mL.
Convert to units: mL × 100.

Units for a range of doses, from a 5 mg vial reconstituted with 2 mL of bacteriostatic water (2.5 mg/mL).

Dose	Volume	U-100 units
100 mcg	0.04 mL	4 units
250 mcg	0.10 mL	10 units
500 mcg	0.20 mL	20 units
750 mcg	0.30 mL	30 units
1,000 mcg	0.40 mL	40 units

That table is only valid at 2.5 mg/mL. At any other concentration every row changes, which is exactly why the converter and the reconstitution calculator ask for the vial strength and water volume rather than assuming them.

Units to milligrams

A syringe unit is a volume mark, 0.01 mL on a U-100 barrel, not an amount of medicine. How many mg a number of units holds depends on the vial: divide the vial mg by the water mL to get its concentration, then multiply by the units and divide by 100.

Milligrams in a number of U-100 units, by vial concentration.

Units	1 mg/mL	2 mg/mL	2.5 mg/mL	5 mg/mL	10 mg/mL
10 units	0.1 mg	0.2 mg	0.25 mg	0.5 mg	1 mg
12 units	0.12 mg	0.24 mg	0.3 mg	0.6 mg	1.2 mg
20 units	0.2 mg	0.4 mg	0.5 mg	1 mg	2 mg
25 units	0.25 mg	0.5 mg	0.625 mg	1.25 mg	2.5 mg
30 units	0.3 mg	0.6 mg	0.75 mg	1.5 mg	3 mg
50 units	0.5 mg	1 mg	1.25 mg	2.5 mg	5 mg

Insulin syringe FAQs.

The conversions people search for most: units to mL, mg and mcg to units, and back again.

How many units is 1 mL on an insulin syringe?

100 units on a U-100 syringe, so 1 unit is 0.01 mL. That makes 0.1 mL 10 units, 0.2 mL 20 units and 0.25 mL 25 units. To convert any volume, multiply the mL by 100.

How many mL is 10 units on an insulin syringe?

0.1 mL on a U-100 syringe, the common kind. Divide the units by 100 to get mL. On a U-40 syringe 10 units is 0.25 mL, so check the scale printed on the barrel.

How do I convert mg or mcg to insulin syringe units?

You need the vial's concentration: divide the vial mg by the water mL. Then divide the dose in mg by that concentration to get mL, and multiply by 100 for units. For 0.2 mg from a 5 mg vial mixed with 2 mL (2.5 mg/mL), 0.2 ÷ 2.5 is 0.08 mL, which is 8 units. For a dose in mcg, divide by 1,000 first.

What is 2 mg on a 100 unit syringe?

It depends on the vial. At 5 mg/mL, such as a 10 mg vial mixed with 2 mL of water, 2 mg is 0.4 mL, which is 40 units. At 2.5 mg/mL it is 80 units. The converter above works it out for your vial.

How many units is 300 mcg on an insulin syringe?

12 units at 2.5 mg/mL, such as a 5 mg vial mixed with 2 mL of water. At 5 mg/mL it is 6 units.

How many mg is 50 units on an insulin syringe?

50 units is 0.5 mL on a U-100 syringe, so the mg depends on the concentration: 1.25 mg at 2.5 mg/mL, 2.5 mg at 5 mg/mL and 5 mg at 10 mg/mL. In the same way, 12 units is 0.3 mg at 2.5 mg/mL.

Is a unit on an insulin syringe the same as a unit of insulin?

Only when U-100 insulin is drawn into a U-100 syringe, where each line holds one unit of insulin. Otherwise a syringe unit is a volume mark, 0.01 mL, and what it holds depends on the liquid. A mismatch changes the dose: U-40 insulin drawn to the 10 unit line of a U-100 syringe delivers 4 units. Check any mismatch with your pharmacist or healthcare professional.

Convert units, mL and mg.

How to read a U-100 syringe.

Check the barrel scale

Convert units and mL

Add the concentration

Units to millilitres

Millilitres to units

The three common barrel sizes

Micrograms to units

Units to milligrams

Insulin syringe FAQs.

Peptide reconstitution calculator

Read a U-100 syringe

Subcutaneous injection sites

How to dispose of needles