Tools · Dose, made simple

Units, mg, mL.
Made simple.

Pharmacies send 30, 50 or 100 unit syringes, and vials come in different strengths. Here is what every number means, and a quick calculator to double check your draw.

Woman at her kitchen table holding a medication vial with a curious smile

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Always check your labelYour prescription and vial label are the final word. Concentrations change between pharmacies and refills, so your units may not match what you used before. Not sure? Message your care team before you inject.

The four numbers

What it all means.

mgDose

How much medicine you take. Your prescription tells you this, like 0.25 mg.

Example: 0.25 mg a week

mg/mLConcentration

How much medicine is packed into each mL of liquid in your vial. It is printed on your vial label.

Example: 2.5 mg/mL

mLVolume

How much liquid you draw up. Dose divided by concentration.

0.25 mg / 2.5 mg/mL = 0.1 mL

unitsSyringe marks

The tick marks on an insulin syringe. On a standard U-100 syringe, 100 units = 1 mL.

0.1 mL = 10 units

Syringe sizes

Same units, different sizes.

50 unit syringe (0.5 mL)

Each small line is usually 1 unit. It holds up to 0.5 mL. Good for smaller doses because the lines are easier to read.

100 unit syringe (1 mL)

Each small line is usually 2 units. It holds up to 1 mL. The number of units for your dose is the same as on a 50 unit syringe, only the scale is different.

30 unit syringe (0.3 mL)

Often marked in half or single units. Holds up to 0.3 mL, for very small doses like microdosing.

Units are not mg

Units measure liquid on the syringe, not the amount of medicine. 10 units of one vial can hold a different dose than 10 units of another vial if the concentration is different.

Double check your drawYour dose (mg, from your prescription)Vial concentration (mg/mL, from your vial label)

Syringe you were sent

For U-100 insulin syringes only. Education tool, not medical advice. Follow your prescription, pharmacy label and provider instructions.

Draw up to

10 units

That is 0.10 mL of liquid.Questions? Message your care team →

FAQ

Good questions.

Kind answers.

How many units is 0.25 mg?

It depends on your vial concentration. Divide your dose in mg by the concentration in mg/mL to get mL, then multiply by 100 for units on a U-100 syringe. At 2.5 mg/mL, 0.25 mg is 0.1 mL, which is 10 units. Always follow your own prescription and vial label.

Is a 50 unit syringe different from a 100 unit syringe?

The units mean the same thing on both. A 50 unit syringe holds 0.5 mL and a 100 unit syringe holds 1 mL. Your dose in units stays the same, only the size and spacing of the lines change, so read the scale on the syringe you were sent.

Why are my units different from my last refill?

Pharmacies can prepare vials at different concentrations, so the same dose in mg can mean a different number of units. Always check your newest prescription and vial label, and message your care team before injecting if anything looks different.

?Not sure what you need?

Units, mg, mL.Made simple.

What it all means.

Same units, different sizes.

Good questions.

Units, mg, mL.
Made simple.