Use this semaglutide calculator to convert vial strength, reconstitution volume, and target dose into the amount to draw on your syringe. The page focuses on the math, not medical advice.
- Common vial examples
- 2.5 / 5 / 10 mg
- Example starting dose
- 0.25 mg
- Common syringe
- U-100 insulin
- Last reviewed
Storage before and after reconstitution: Lyophilised 2–8°C; reconstituted vial refrigerated and used within the pharmacy beyond-use date.
Quick answers: Semaglutide doses in units
The units depend on the concentration: the mg/mL printed on a premixed vial, or your vial's mg divided by the mL of water you added. On a U-100 insulin syringe (100 units = 1 mL):
- How many units is 0.25 mg of semaglutide?
- 25 units (0.25 mL) at 1 mg/mL10 units (0.1 mL) at 2.5 mg/mL5 units (0.05 mL) at 5 mg/mL
- How many units is 0.5 mg of semaglutide?
- 50 units (0.5 mL) at 1 mg/mL20 units (0.2 mL) at 2.5 mg/mL10 units (0.1 mL) at 5 mg/mL
- How many units is 1 mg of semaglutide?
- 100 units (1 mL) at 1 mg/mL40 units (0.4 mL) at 2.5 mg/mL20 units (0.2 mL) at 5 mg/mL
- How many units is 1.7 mg of semaglutide?
- 170 units (1.7 mL, over 1 mL) at 1 mg/mL68 units (0.68 mL) at 2.5 mg/mL34 units (0.34 mL) at 5 mg/mL
- How many units is 2.4 mg of semaglutide?
- 240 units (2.4 mL, over 1 mL) at 1 mg/mL96 units (0.96 mL) at 2.5 mg/mL48 units (0.48 mL) at 5 mg/mL
Educational maths only, not a dose recommendation. Use the calculator above for your own vial, water volume and syringe.
Quick math example
A 5 mg vial mixed with 2 mL gives 2.5 mg/mL. A 0.25 mg dose is 0.1 mL, which equals 10 units on a U-100 syringe.
Semaglutide reconstitution reference
U-100 units to draw for each common Semaglutide dose, by vial size, reconstituted with 2 mL of bacteriostatic water. Change the water volume in the calculator above to recompute for your own setup.
| Vial | Concentration | 250 mcg | 500 mcg | 1 mg | 1.7 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 2.5 mg | 1.25 mg/mL | 20 u(0.2 mL) | 40 u(0.4 mL) | 80 u(0.8 mL) | 136 u(1.36 mL) | 192 u(1.92 mL) |
| 5 mg | 2.5 mg/mL | 10 u(0.1 mL) | 20 u(0.2 mL) | 40 u(0.4 mL) | 68 u(0.68 mL) | 96 u(0.96 mL) |
| 10 mg | 5 mg/mL | 5 u(0.05 mL) | 10 u(0.1 mL) | 20 u(0.2 mL) | 34 u(0.34 mL) | 48 u(0.48 mL) |
Swipe the table to see every dose →
Educational reference only — not a dose recommendation. Units assume a U-100 insulin syringe (100 units = 1 mL on U-100). Always confirm against your own vial, diluent, and clinician or pharmacy instructions.
How the semaglutide calculation works
The calculator first converts the vial amount from mg to mcg, then divides by the BAC water volume to find concentration. Your target dose is divided by that concentration to return mL and syringe units.
For GLP-1 compounds, small dose changes can meaningfully change the draw volume. Re-run the calculation whenever vial size, water amount, syringe type, or target dose changes.
- Concentration = vial mcg / water mL
- Dose volume = target dose mcg / concentration
- U-100 units = dose volume mL x 100
Semaglutide 2 mg vial examples
A 2 mg vial in 1 mL gives 2 mg/mL (2,000 mcg/mL). A 0.25 mg dose is 0.125 mL, about 12–13 units; a 0.5 mg dose is 0.25 mL (25 units).
A 2 mg vial covers early titration only. As the dose increases it empties quickly, so most people move to a 5 or 10 mg vial once they pass the starting steps.
- 2 mg / 1 mL = 2 mg/mL → 0.25 mg = ~12.5 units
- 2 mg / 2 mL = 1 mg/mL → 0.25 mg = 0.25 mL = 25 units
- A 2 mg vial yields about eight 0.25 mg doses
Semaglutide 2 mg vial: units per dose (1 mL BAC water)
U-100 units to draw for each common Semaglutide dose, by vial size, reconstituted with 1 mL of bacteriostatic water. Change the water volume in the calculator above to recompute for your own setup.
| Vial | Concentration | 250 mcg | 500 mcg | 1 mg | 1.7 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 2 mg | 2 mg/mL | 12.5 u(0.13 mL) | 25 u(0.25 mL) | 50 u(0.5 mL) | 85 u(0.85 mL) | 120 u(1.2 mL) |
Swipe the table to see every dose →
Educational reference only — not a dose recommendation. Units assume a U-100 insulin syringe (100 units = 1 mL on U-100). Always confirm against your own vial, diluent, and clinician or pharmacy instructions.
Semaglutide 5 mg vial with 2 mL example
A 5 mg semaglutide vial mixed with 2 mL gives a concentration of 2.5 mg/mL, or 2,500 mcg/mL.
A 0.25 mg dose is 250 mcg. At 2,500 mcg/mL, that dose is 0.1 mL, which equals 10 units on a U-100 syringe.
- 5 mg / 2 mL = 2.5 mg/mL
- 0.25 mg = 250 mcg
- 250 mcg / 2,500 mcg per mL = 0.1 mL = 10 U-100 units
Semaglutide 5 mg vial: units per dose (2 mL BAC water)
U-100 units to draw for each common Semaglutide dose, by vial size, reconstituted with 2 mL of bacteriostatic water. Change the water volume in the calculator above to recompute for your own setup.
| Vial | Concentration | 250 mcg | 500 mcg | 1 mg | 1.7 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 5 mg | 2.5 mg/mL | 10 u(0.1 mL) | 20 u(0.2 mL) | 40 u(0.4 mL) | 68 u(0.68 mL) | 96 u(0.96 mL) |
Swipe the table to see every dose →
Educational reference only — not a dose recommendation. Units assume a U-100 insulin syringe (100 units = 1 mL on U-100). Always confirm against your own vial, diluent, and clinician or pharmacy instructions.
Semaglutide 10 mg vial with 2 mL example
A 10 mg semaglutide vial mixed with 2 mL gives a concentration of 5 mg/mL, or 5,000 mcg/mL.
A 0.5 mg dose is 500 mcg. At 5,000 mcg/mL, that dose is 0.1 mL, which equals 10 U-100 units.
- 10 mg / 2 mL = 5 mg/mL
- 0.5 mg = 500 mcg
- 500 mcg / 5,000 mcg per mL = 0.1 mL = 10 U-100 units
Semaglutide 10 mg vial: units per dose (2 mL BAC water)
U-100 units to draw for each common Semaglutide dose, by vial size, reconstituted with 2 mL of bacteriostatic water. Change the water volume in the calculator above to recompute for your own setup.
| Vial | Concentration | 250 mcg | 500 mcg | 1 mg | 1.7 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 10 mg | 5 mg/mL | 5 u(0.05 mL) | 10 u(0.1 mL) | 20 u(0.2 mL) | 34 u(0.34 mL) | 48 u(0.48 mL) |
Swipe the table to see every dose →
Educational reference only — not a dose recommendation. Units assume a U-100 insulin syringe (100 units = 1 mL on U-100). Always confirm against your own vial, diluent, and clinician or pharmacy instructions.
Semaglutide dose-to-units chart (5 mg vial in 2 mL)
With a 5 mg vial reconstituted in 2 mL (2.5 mg/mL, or 2,500 mcg/mL), the standard titration doses fall on the unit marks below. At this concentration every 0.25 mg of dose is 0.1 mL, which is 10 units on a U-100 syringe.
This chart is for the 5 mg / 2 mL setup only. A different vial size or water volume changes the concentration and the units — enter your own figures in the calculator to regenerate them.
- 0.25 mg = 0.10 mL = 10 units
- 0.5 mg = 0.20 mL = 20 units
- 1.0 mg = 0.40 mL = 40 units
- 1.7 mg = 0.68 mL = 68 units
- 2.4 mg = 0.96 mL = 96 units
How much BAC water for semaglutide
The water you add sets the concentration; the dose decides the draw. For a 5 mg vial: 1 mL gives 5 mg/mL (0.25 mg = 5 units), 2 mL gives 2.5 mg/mL (0.25 mg = 10 units), and 3 mL gives 1.67 mg/mL (0.25 mg = 15 units).
More water makes small doses easier to measure accurately, because the draw lands on more unit lines. Choose the volume up front for your whole titration rather than topping up a vial that is already mixed.
- 5 mg / 1 mL = 5 mg/mL → 0.25 mg = 5 units
- 5 mg / 2 mL = 2.5 mg/mL → 0.25 mg = 10 units
- 5 mg / 3 mL = 1.67 mg/mL → 0.25 mg = 15 units
Semaglutide doses in units by concentration
Semaglutide units depend on the concentration in the vial. A 5 mg vial mixed with 2 mL is 2.5 mg/mL, and compounded vials often come premixed with the strength on the label, for example 1, 2.5 or 5 mg/mL. At 5 mg/mL a 0.25 mg dose is only 5 units, while at 1 mg/mL it is 25 units, so the same dose can be five times as many units from one vial as from another.
The rows follow the weekly steps on the Wegovy label: 0.25 mg for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, then 2.4 mg (Ozempic's steps stop at 2 mg). A compounded prescription may differ, so use the dose your prescriber wrote and the concentration on your own label.
- 0.25 mg at 2.5 mg/mL = 0.1 mL = 10 units
- 0.25 mg at 5 mg/mL = 0.05 mL = 5 units
- 1 mg at 2.5 mg/mL = 0.4 mL = 40 units
Semaglutide dose to U-100 units by concentration
| DoseWegovy label step | 1 mg/mLconcentration | 2.5 mg/mLconcentration | 5 mg/mLconcentration |
|---|---|---|---|
| 0.25 mgWeeks 1–4 | 25 u(0.25 mL) | 10 u(0.1 mL) | 5 u(0.05 mL) |
| 0.5 mgWeeks 5–8 | 50 u(0.5 mL) | 20 u(0.2 mL) | 10 u(0.1 mL) |
| 1 mgWeeks 9–12 | 100 u(1 mL) | 40 u(0.4 mL) | 20 u(0.2 mL) |
| 1.7 mgWeeks 13–16 | 170 u(1.7 mL)over 1 mL | 68 u(0.68 mL) | 34 u(0.34 mL) |
| 2.4 mgWeek 17 on | 240 u(2.4 mL)over 1 mL | 96 u(0.96 mL) | 48 u(0.48 mL) |
Swipe the table to see every vial →
Educational reference only — not a dose recommendation. Units assume a U-100 insulin syringe (100 units = 1 mL on U-100). Confirm against your own vial label, diluent, and clinician or pharmacy instructions.
How many mg is 40 units of semaglutide?
Units ÷ 100 gives mL on a U-100 syringe, and mL × the concentration gives mg. 40 units is 0.4 mL: 0.4 mg at 1 mg/mL, 1 mg at 2.5 mg/mL and 2 mg at 5 mg/mL. 20 units is 0.2 mg, 0.5 mg or 1 mg at the same three strengths.
The FDA has warned about compounded semaglutide dosing errors in which patients drew 5 to 20 times the intended dose after confusing units with mL. Check the mg/mL on your label against the units you were told to draw, and recheck whenever a new vial arrives, because the strength can change between refills.
- mg = units ÷ 100 × mg/mL
- 20 units at 2.5 mg/mL = 0.5 mg
- 40 units at 5 mg/mL = 2 mg
Semaglutide units to mg by concentration
| U-100 units | 1 mg/mL | 2.5 mg/mL | 5 mg/mL |
|---|---|---|---|
| 5 units0.05 mL | 0.05 mg | 0.125 mg | 0.25 mg |
| 10 units0.1 mL | 0.1 mg | 0.25 mg | 0.5 mg |
| 20 units0.2 mL | 0.2 mg | 0.5 mg | 1 mg |
| 25 units0.25 mL | 0.25 mg | 0.625 mg | 1.25 mg |
| 40 units0.4 mL | 0.4 mg | 1 mg | 2 mg |
| 50 units0.5 mL | 0.5 mg | 1.25 mg | 2.5 mg |
| 100 units1 mL | 1 mg | 2.5 mg | 5 mg |
Educational reference only. On a U-100 insulin syringe 100 units = 1 mL, so mg = units ÷ 100 × the mg/mL on your vial label. The same number of units holds a different dose at every concentration, so always read the label.
Use with compounded or lyophilized vials
This page is intended for situations where you need to calculate a dose from a vial and diluent volume. Pre-filled commercial pens usually do not require this math.
Follow the label, pharmacy directions, and clinician instructions for storage, titration, and beyond-use dates.
Frequently asked questions
What are the semaglutide doses in syringe units?
Does this calculator tell me what semaglutide dose to take?
Why do the units change when I change syringe type?
Should I use bacteriostatic water?
How much bacteriostatic water should I add to semaglutide?
How many doses are in a 2 mg semaglutide vial?
How many units is 0.25 mg of semaglutide?
How many mg is 20 units of semaglutide?
How many mg is 40 units of semaglutide?
My semaglutide vial is already mixed. How do I use the calculator?
Primary sources
Background references for this calculator. PepSync does not make clinical claims; these citations support the educational context only.