How many units is 2.5 mg of tirzepatide?

It depends on the vial. In a brand single-dose vial (2.5 mg/0.5 mL) it is 0.5 mL, which is 50 units. In a brand multi-dose vial (10 mg/2.4 mL) it is 0.6 mL, which is 60 units. In a compounded vial at 10 mg/mL it is 0.25 mL, which is 25 units. The formula is mL = mg ÷ (mg/mL), then units = mL × 100.

How many mg is 20 units of tirzepatide?

20 units is 0.2 mL on a U-100 syringe. The mg depends on the concentration: 1 mg at 5 mg/mL, 2 mg at 10 mg/mL, 4 mg at 20 mg/mL. Multiply 0.2 by the mg/mL on your label.

How many mg is 40 units or 50 units of tirzepatide?

40 units is 0.4 mL and 50 units is 0.5 mL. At 10 mg/mL that is 4 mg and 5 mg. In a brand single-dose vial, 50 units (0.5 mL) is the whole vial, which is the dose printed on its label.

What is a unit on an insulin syringe?

A unit is a volume mark. On a U-100 syringe 100 units equal 1 mL, so 1 unit is 0.01 mL. A 0.3 mL syringe holds 30 units, a 0.5 mL syringe 50 units and a 1 mL syringe 100 units.

Why is a brand vial dose 50 or 60 units and not 25?

Brand vials are filled so the dose is always the same volume: 0.5 mL (50 units) from a single-dose vial and 0.6 mL (60 units) from a multi-dose vial. The 25-unit figure only applies to a 10 mg/mL concentration, which is not how the brand vials are made.

Which syringe does the brand vial label call for?

The Zepbound and Mounjaro labels tell vial users to use a 1 mL syringe that can measure 0.5 mL or 0.6 mL, with a new syringe and needle each time. For compounded vials, follow the instructions that came with your prescription.

Can this convert a semaglutide dose to tirzepatide?

No. Semaglutide and tirzepatide are different drugs and there is no dose conversion between them. This site only converts units, mL and mg of the same drug.

Tirzepatide Units to mg Calculator

Convert tirzepatide units to mg, or mg to units, for the vial you actually have. This dosage calculator starts with the vial strength (a brand single-dose or multi-dose vial, or the mg/mL on a compounded vial's label) and then writes out each step, so you can check the dosage in units yourself.

Why the vial first: “2.5 mg = 25 units” is only true at 10 mg/mL. A brand single-dose vial dose is always 0.5 mL (50 units) and a brand multi-dose vial dose is always 0.6 mL (60 units).

Follow your prescription and pharmacy label. Ask the prescriber or pharmacist if anything is unclear.

1. Which vial?

Brand vial (Zepbound / Mounjaro)Compounded vial

Vial type

Single-doseMulti-dose

Strength on the vial label

Concentration: 5 mg ÷ 0.5 mL = 10 mg/mL. The label dose is 0.5 mL, the whole vial.

2. Convert

mg → unitsunits → mg

Dose in mg

3. Syringe (U-100)

0.3 mL · 30 units0.5 mL · 50 units1 mL · 100 units

5 mg = 50 units(0.5 mL at 10 mg/mL)

Step 1. Concentration: mg/mL = mg in vial ÷ mL in vial
5 mg ÷ 0.5 mL = 10 mg/mL
Step 2. Volume: mL = mg ÷ (mg/mL)
5 ÷ (5 ÷ 0.5) = 0.5 mL
Step 3. Units on a U-100 syringe: units = mL × 100
0.5 × 100 = 50 units

How to use this dosage calculator

Choose the vial: a brand vial (pick the strength printed on it) or a compounded vial (type its mg/mL).
Choose the direction, mg → units or units → mg, and enter the number.
Choose the syringe size. The drawing shows where the mark is, and you get a warning if it does not fit.
Compare every step with your pharmacy label. If anything differs, ask the pharmacist.

Tirzepatide units to mg: the formulas

Two lines cover every case: mL = mg ÷ (mg/mL) and units = mL × 100. Going the other way, mL = units ÷ 100 and mg = mL × (mg/mL). Four worked examples:

Brand single-dose vial, 5 mg/0.5 mL: 5 mg in units

Concentration: 5 mg ÷ 0.5 mL = 10 mg/mL
Volume: 5 ÷ (5 ÷ 0.5) = 0.5 mL
Units on a U-100 syringe: 0.5 × 100 = 50 units

Result: 5 mg = 0.5 mL = 50 units

Brand multi-dose vial, 10 mg/2.4 mL: 2.5 mg in units

Concentration: 10 mg ÷ 2.4 mL = 4.167 mg/mL
Volume: 2.5 ÷ (10 ÷ 2.4) = 0.6 mL
Units on a U-100 syringe: 0.6 × 100 = 60 units

Result: 2.5 mg = 0.6 mL = 60 units

Compounded vial, 10 mg/mL: 2.5 mg in units

Concentration: 10 mg/mL (from the pharmacy label)
Volume: 2.5 ÷ 10 = 0.25 mL
Units on a U-100 syringe: 0.25 × 100 = 25 units

Result: 2.5 mg = 0.25 mL = 25 units

Compounded vial, 20 mg/mL: 20 units in mg

Concentration: 20 mg/mL (from the pharmacy label)
Volume: 20 ÷ 100 = 0.2 mL
Dose: 0.2 × 20 = 4 mg

Result: 4 mg = 0.2 mL = 20 units

Tirzepatide dosage in units: brand vials

Every brand dose is the same volume, so the dosage in units is 50 for a single-dose vial and 60 for a multi-dose vial, whatever the mg. The multi-dose concentration is the total divided by 2.4 mL (for example 10 mg ÷ 2.4 mL), not the rounded 4.17 mg/mL. Tap a dose for its own page.

Tirzepatide brand vials (Zepbound and Mounjaro labels, section 3)
Dose	Single-dose vial	Draw	Multi-dose vial	Draw
2.5 mg	2.5 mg/0.5 mL	0.5 mL = 50 units	10 mg/2.4 mL (4.17 mg/mL)	0.6 mL = 60 units
5 mg	5 mg/0.5 mL	0.5 mL = 50 units	20 mg/2.4 mL (8.33 mg/mL)	0.6 mL = 60 units
7.5 mg	7.5 mg/0.5 mL	0.5 mL = 50 units	30 mg/2.4 mL (12.5 mg/mL)	0.6 mL = 60 units
10 mg	10 mg/0.5 mL	0.5 mL = 50 units	40 mg/2.4 mL (16.67 mg/mL)	0.6 mL = 60 units
12.5 mg	12.5 mg/0.5 mL	0.5 mL = 50 units	50 mg/2.4 mL (20.83 mg/mL)	0.6 mL = 60 units
15 mg	15 mg/0.5 mL	0.5 mL = 50 units	60 mg/2.4 mL (25 mg/mL)	0.6 mL = 60 units

Compounded vials

Compounded tirzepatide dosage in units depends entirely on the concentration the pharmacy used, which is printed on the vial label as mg/mL (sometimes as a total, such as 20 mg in 2 mL, which is 10 mg/mL). The calculator gives no result until you enter it, because guessing would be wrong more often than right. The same 2.5 mg dose at five different concentrations:

Compounded vials: mL and units at example concentrations
Dose	5 mg/mL	10 mg/mL	15 mg/mL	20 mg/mL	25 mg/mL
2.5 mg	0.5 mL = 50 u	0.25 mL = 25 u	0.167 mL = 16.7 u	0.125 mL = 12.5 u	0.1 mL = 10 u

See the tirzepatide dosage chart for every labeled dose at these concentrations.

Units to mg table

How many mg are in common unit marks. Find the column for your vial's concentration; if it is not listed, use the calculator. The columns are the round mg/mL values of the brand single-dose vials, up to 25 mg/mL.

How many mg of tirzepatide is in a given number of units
Units	mL	at 5 mg/mL	at 10 mg/mL	at 15 mg/mL	at 20 mg/mL	at 25 mg/mL
10 units	0.1 mL	0.5 mg	1 mg	1.5 mg	2 mg	2.5 mg
20 units	0.2 mL	1 mg	2 mg	3 mg	4 mg	5 mg
25 units	0.25 mL	1.25 mg	2.5 mg	3.75 mg	5 mg	6.25 mg
30 units	0.3 mL	1.5 mg	3 mg	4.5 mg	6 mg	7.5 mg
40 units	0.4 mL	2 mg	4 mg	6 mg	8 mg	10 mg
50 units	0.5 mL	2.5 mg	5 mg	7.5 mg	10 mg	12.5 mg
60 units	0.6 mL	3 mg	6 mg	9 mg	12 mg	15 mg

Units vs mg

A mg (milligram) is the amount of tirzepatide. A unit is a mark on a U-100 insulin syringe, and on a U-100 syringe 100 units fill 1 mL, so 1 unit is 0.01 mL. Units measure volume, not drug. How much tirzepatide is in those units depends on how concentrated the liquid is.

Why the vial concentration matters

The same dose can be very different volumes. 2.5 mg is 25 units only at 10 mg/mL. At 5 mg/mL it is 50 units, and at 25 mg/mL it is 10 units. That is why this calculator asks for the vial first and never assumes a concentration.

Brand vs compounded vials

Brand tirzepatide vials (Zepbound and Mounjaro) are made so every dose is the same volume: 0.5 mL (50 units) from a single-dose vial, or 0.6 mL (60 units) from a multi-dose vial that holds 4 doses. The vial strength changes with the dose instead. Compounded vials are prepared by a pharmacy at a concentration of its choosing, so the volume for a given dose changes from vial to vial. Read the mg/mL on the pharmacy label.

Tirzepatide dose escalation in the FDA labels

The Zepbound and Mounjaro labels start at 2.5 mg once weekly for 4 weeks. 2.5 mg is only for starting treatment, not a maintenance dose. After that the dose goes up in 2.5 mg steps, with at least 4 weeks on each dose. Zepbound lists 5 mg, 10 mg or 15 mg as maintenance doses for weight reduction and 10 mg or 15 mg for obstructive sleep apnea. The maximum is 15 mg once weekly. The weeks in the table are the earliest a dose can start under the label; the prescriber decides the actual schedule.

The dosage chart lists each step with its mL and units.

Frequently asked questions

How many units is 2.5 mg of tirzepatide?: It depends on the vial. In a brand single-dose vial (2.5 mg/0.5 mL) it is 0.5 mL, which is 50 units. In a brand multi-dose vial (10 mg/2.4 mL) it is 0.6 mL, which is 60 units. In a compounded vial at 10 mg/mL it is 0.25 mL, which is 25 units. The formula is mL = mg ÷ (mg/mL), then units = mL × 100.
How many mg is 20 units of tirzepatide?: 20 units is 0.2 mL on a U-100 syringe. The mg depends on the concentration: 1 mg at 5 mg/mL, 2 mg at 10 mg/mL, 4 mg at 20 mg/mL. Multiply 0.2 by the mg/mL on your label.
How many mg is 40 units or 50 units of tirzepatide?: 40 units is 0.4 mL and 50 units is 0.5 mL. At 10 mg/mL that is 4 mg and 5 mg. In a brand single-dose vial, 50 units (0.5 mL) is the whole vial, which is the dose printed on its label.
What is a unit on an insulin syringe?: A unit is a volume mark. On a U-100 syringe 100 units equal 1 mL, so 1 unit is 0.01 mL. A 0.3 mL syringe holds 30 units, a 0.5 mL syringe 50 units and a 1 mL syringe 100 units.
Why is a brand vial dose 50 or 60 units and not 25?: Brand vials are filled so the dose is always the same volume: 0.5 mL (50 units) from a single-dose vial and 0.6 mL (60 units) from a multi-dose vial. The 25-unit figure only applies to a 10 mg/mL concentration, which is not how the brand vials are made.
Which syringe does the brand vial label call for?: The Zepbound and Mounjaro labels tell vial users to use a 1 mL syringe that can measure 0.5 mL or 0.6 mL, with a new syringe and needle each time. For compounded vials, follow the instructions that came with your prescription.
Can this convert a semaglutide dose to tirzepatide?: No. Semaglutide and tirzepatide are different drugs and there is no dose conversion between them. This site only converts units, mL and mg of the same drug.

Sources

Zepbound (tirzepatide) prescribing information (DailyMed, effective 2026-08-28)
Mounjaro (tirzepatide) prescribing information (DailyMed, effective 2026-08-27)

Doses and vial strengths checked against these labels on 2026-10-22.