Insulin Syringe Units to mL: Conversion Chart
On a U-100 insulin syringe, 100 units is 1 mL, so 1 unit is 0.01 mL and 10 units is 0.1 mL. The charts below convert every common amount both ways and show which barrel it fits. What they cannot tell you is how many units a dose in milligrams works out to; that depends on how much water went into the vial, which is what the calculator is for.
Last edited · written by PepPrep · not medical advice
Insulin syringes are marked in units, and almost everything else is measured in millilitres. This page is the lookup table, nothing more; what to measure is between you and a clinician.
On any standard U-100 syringe, 100 units = 1 mL. Every number below follows from that one fact: units ÷ 100 = mL, and mL × 100 = units. So 35 units is 0.35 mL, and 0.12 mL is 12 units.
Units to mL
| Units | Millilitres | Fits which syringe |
|---|---|---|
| 1 unit | 0.01 mL | 0.3 mL · 0.5 mL · 1 mL |
| 2 units | 0.02 mL | 0.3 mL · 0.5 mL · 1 mL |
| 5 units | 0.05 mL | 0.3 mL · 0.5 mL · 1 mL |
| 8 units | 0.08 mL | 0.3 mL · 0.5 mL · 1 mL |
| 10 units | 0.10 mL | 0.3 mL · 0.5 mL · 1 mL |
| 12 units | 0.12 mL | 0.3 mL · 0.5 mL · 1 mL |
| 15 units | 0.15 mL | 0.3 mL · 0.5 mL · 1 mL |
| 20 units | 0.20 mL | 0.3 mL · 0.5 mL · 1 mL |
| 22 units | 0.22 mL | 0.3 mL · 0.5 mL · 1 mL |
| 25 units | 0.25 mL | 0.3 mL · 0.5 mL · 1 mL |
| 30 units | 0.30 mL | 0.3 mL (full) · 0.5 mL · 1 mL |
| 35 units | 0.35 mL | 0.5 mL · 1 mL |
| 40 units | 0.40 mL | 0.5 mL · 1 mL |
| 45 units | 0.45 mL | 0.5 mL · 1 mL |
| 50 units | 0.50 mL | 0.5 mL (full) · 1 mL |
| 60 units | 0.60 mL | 1 mL |
| 70 units | 0.70 mL | 1 mL |
| 75 units | 0.75 mL | 1 mL |
| 80 units | 0.80 mL | 1 mL |
| 90 units | 0.90 mL | 1 mL |
| 100 units | 1.00 mL | 1 mL (full) |
Most 1 mL barrels are printed with a line every 2 units, so odd amounts such as 15, 25 or 35 units sit halfway between two lines. The 0.3 and 0.5 mL barrels have a line for every unit, and the half-unit 0.3 mL barrel one for every half unit, which is why small amounts are easier to read on a small barrel.
mL to units
| Millilitres | Units | Where it sits |
|---|---|---|
| 0.01 mL | 1 unit | The smallest whole line on a 0.3 or 0.5 mL barrel |
| 0.02 mL | 2 units | The first line on most 1 mL barrels |
| 0.05 mL | 5 units | |
| 0.08 mL | 8 units | |
| 0.1 mL | 10 units | The "10" line on every U-100 barrel |
| 0.125 mL | 12.5 units | Only the half-unit 0.3 mL barrel has a line here |
| 0.15 mL | 15 units | Between two lines on most 1 mL barrels |
| 0.18 mL | 18 units | |
| 0.2 mL | 20 units | |
| 0.25 mL | 25 units | Between two lines on most 1 mL barrels |
| 0.3 mL | 30 units | A full 0.3 mL syringe |
| 0.4 mL | 40 units | |
| 0.5 mL | 50 units | A full 0.5 mL syringe |
| 0.6 mL | 60 units | |
| 0.75 mL | 75 units | Between two lines on most 1 mL barrels |
| 0.8 mL | 80 units | |
| 1 mL | 100 units | A full 1 mL syringe |
| 1.25 mL | 125 units | More than any insulin syringe holds |
| 2 mL | 200 units | More than any insulin syringe holds |
| 3 mL | 300 units | A full 3 mL luer-lock syringe, which is marked in mL, not units |
Anything over 1 mL is more than an insulin syringe holds. For those volumes, such as the water you add when mixing, a 3 mL luer-lock syringe marked in millilitres is the tool.
Quick answers
How many units are in 1 mL?
100, on a U-100 syringe. That is what U-100 means: 100 units to the millilitre.
Is 1 unit 0.01 mL?
Yes, on any U-100 syringe. So 10 units is 0.1 mL and 50 units is 0.5 mL, whichever barrel size you use.
How much is 0.5 mL in units?
50 units, which is exactly one full 0.5 mL syringe.
Where is 0.15 mL or 0.25 mL on a 1 mL syringe?
At 15 and 25 units. On a 1 mL barrel marked every 2 units, both fall halfway between two printed lines (14 and 16, 24 and 26). On a 0.3 or 0.5 mL barrel each has a line of its own. The reading guide shows where to look on the barrel.
Are IU the same as the units on the syringe?
Not necessarily. The units printed on an insulin syringe measure volume: each one is 0.01 mL of whatever is in the barrel. An IU (international unit) on a product label measures how much of the substance there is. How many syringe units hold one IU depends on how much liquid the product was mixed with: IU in the vial ÷ mL of water added gives IU per mL, and one syringe unit holds a hundredth of that.
Units are not a measure of anything in the vial
A unit on the syringe is a hundredth of a millilitre of liquid. It says nothing about how much is dissolved in that liquid; that depends entirely on how much water went into the vial. Two vials mixed with different amounts of water give different amounts per unit. The syringe cannot know that; only your label can. The reconstitution calculator does that arithmetic from the vial size and the water you added.
U-40 syringes exist and are a trap
Some veterinary insulin syringes are marked U-40: 40 units to the millilitre, so every line is worth two and a half times more liquid than on a U-100 barrel, and nothing on this page applies to them. Others sold as veterinary, including the half-unit syringes in the US and Canada, are ordinary U-100 syringes. The two look almost identical, so go by the scale printed on the barrel, not the word on the box: check it says U-100 before you buy, especially outside the US, where U-40 pet syringes show up in the same search results.
If your measurements keep landing between the printed lines, a smaller barrel or a half-unit syringe is the fix. The measuring guide covers the technique.
"How many units is 1 mg?"
As asked, that one has no answer: units measure liquid and milligrams measure the substance dissolved in it, so the same 2 mg can be 20, 40 or 8 units depending on how much water went into the vial. Why milligrams don't translate into a fixed number of syringe units works it through, and the calculator does the arithmetic once you know the vial size and the water volume.
Supplies mentioned: Syringes & Needles · the calculator
Equipment only: nothing on this page is advice about what to inject, how much, or whether a product is fit to use. That comes from the product's labelling and whoever supplied it.