Semaglutide Dosage Calculator: mg to Units (U-100)
A 5 mg vial of Semaglutide mixed with 2 mL of bacteriostatic water holds 2,500 mcg/mL, so a 0.25 mg dose is 0.1 mL — 10 units on a U-100 insulin syringe. Change the vial, water or dose below, or read the chart for other mixes.
Semaglutide dilution chart: 0.25 mg in units
| Vial | + 1 mL water | + 2 mL water | + 3 mL water | Doses per vial |
|---|---|---|---|---|
| 2 mg | 12.5 U 0.125 mL · 2,000 mcg/mL | 25 U 0.25 mL · 1,000 mcg/mL | 37.5 U 0.375 mL · 667 mcg/mL | 8 |
| 5 mg | 5 U 0.05 mL · 5,000 mcg/mL | 10 U 0.1 mL · 2,500 mcg/mL | 15 U 0.15 mL · 1,667 mcg/mL | 20 |
| 10 mg | 2.5 U 0.025 mL · 10,000 mcg/mL | 5 U 0.05 mL · 5,000 mcg/mL | 7.5 U 0.075 mL · 3,333 mcg/mL | 40 |
1 mL = 100 units on a U-100 syringe. Water volume changes the units per dose, never the number of doses in the vial.
Semaglutide titration steps in units (5 mg vial + 2 mL)
| Dose | Units (U-100) | Volume | Context |
|---|---|---|---|
| 0.25 mg | 10 U | 0.1 mL | Weeks 1–4 starting step |
| 0.5 mg | 20 U | 0.2 mL | Weeks 5–8 |
| 1 mg | 40 U | 0.4 mL | Weeks 9–12 |
| 1.7 mg | 68 U | 0.68 mL | Weeks 13–16 (Wegovy schedule) |
| 2.4 mg | 96 U | 0.96 mL | Maintenance (Wegovy schedule) |
Mix: 5 mg vial + 2 mL water = 2,500 mcg/mL. Dose steps are the label titration listed on our semaglutide page. The same mix covers the whole ladder without exceeding one syringe.
Measuring Semaglutide: the math that matters
Semaglutide doses are written in milligrams, but a syringe is marked in units, and the two only connect through the concentration of your vial. With a 5 mg vial and 2 mL of bacteriostatic water the solution is 2,500 mcg/mL, so 0.25 mg is 0.1 mL, or 10 units on a U-100 syringe. With a 10 mg vial and the same 2 mL, 0.25 mg drops to 5 units. The same number of units from two different vials can be two different doses.
This math is for lyophilized powder that has to be mixed. The branded products, Ozempic and Wegovy, come as pre-filled pens where the dose is fixed or selected on the pen itself, so there is nothing to reconstitute and no units to count.
The titration ladder is what makes semaglutide awkward to measure. Doses rise from 0.25 mg to 2.4 mg, nearly a tenfold range, and a mix chosen for the first month may not suit the last. In the 5 mg + 2 mL mix above the ladder runs 10, 20, 40, 68 and 96 units, all within one 1 mL syringe. A 10 mg vial with 1 mL puts the starting dose at 2.5 units, too small to read reliably on a syringe marked every 2 units. A 2 mg vial with 3 mL makes 0.25 mg easy to draw (37.5 units) but holds less than one 2.4 mg dose.
Plan the mix around the doses you will actually draw from that vial. Count doses per vial at the current step: a 5 mg vial covers 20 doses of 0.25 mg but only about two of 2.4 mg. When the step changes mid-vial, keep the same concentration and recalculate units rather than remixing.
Common Semaglutide measuring mistakes
- Reading a prescription written in units without knowing the concentration it was written for. "10 units" is 0.25 mg at 2,500 mcg/mL and 0.5 mg at 5,000 mcg/mL.
- Entering 0.25 with the unit set to mcg. That is a thousand times less than intended, and the result comes out at 0.01 units.
- Carrying the units from the last vial over to a new vial of a different size.
- Moving up a titration step by adding units by feel instead of recalculating from mg.
- Mixing a 10 mg vial with very little water, which leaves the early doses at 2–5 units, where one syringe line is a large share of the dose.