WeightSnap Tools / Semaglutide reconstitution
Enter your semaglutide vial size, how much bacteriostatic water you add, and your dose. Get the concentration, the volume to draw, and the insulin syringe units. Compounded semaglutide vials are commonly 5mg or 10mg. Free, instant, nothing to install.
Common semaglutide vial and bacteriostatic water combinations, with the resulting concentration and the U-100 syringe units for reference dose points. Pure arithmetic; your protocol is between you and your provider.
| Vial + water | Concentration | 0.25 mg | 0.5 mg | 1 mg | 1.7 mg | 2.4 mg |
|---|---|---|---|---|---|---|
| 5 mg + 1 mL | 5 mg/mL | 5 | 10 | 20 | 34 | 48 |
| 5 mg + 2 mL | 2.5 mg/mL | 10 | 20 | 40 | 68 | 96 |
| 10 mg + 1 mL | 10 mg/mL | 2.5 | 5 | 10 | 17 | 24 |
| 10 mg + 2 mL | 5 mg/mL | 5 | 10 | 20 | 34 | 48 |
Units = (dose ÷ concentration) × 100. A U-100 syringe holds 100 units (1 mL); anything over 100 units will not fit in one syringe.
Reconstitution is one division and one multiplication. The water you add sets the concentration, and the concentration turns your dose into a syringe reading.
Worked example: a 5mg semaglutide vial with 2mL of bacteriostatic water gives 2.5 mg/mL. A 0.5mg dose is 0.5 ÷ 2.5 = 0.2 mL, which reads 20 units on a U-100 syringe. Because semaglutide doses are small, the units are small too, so an accurate syringe matters.
Add bacteriostatic water to the powder vial and let it dissolve gently. The water volume sets the concentration: a 5mg vial with 2mL gives 2.5 mg/mL. Enter your vial and water above to see the units for your dose.
Any amount works and only changes the concentration. 1mL gives 5 mg/mL and 2mL gives 2.5 mg/mL. Because semaglutide doses are small, more water can make small doses easier to measure accurately on the syringe.
Divide your dose in mg by the concentration, then multiply by 100. Example: 0.5mg at 2.5 mg/mL is 0.2 mL, or 20 units. The calculator does this for you.
This calculator is for reconstituting powder vials, such as compounded semaglutide. Brand pens (Ozempic, Wegovy) are pre-filled and do not require reconstitution.
No. It converts the numbers you enter into concentration, volume, and units and recommends nothing. Always confirm anything affecting your health with your pharmacist or provider.
WeightSnap is a tracking tool, not medical advice. This calculator performs arithmetic on the numbers you enter and makes no recommendations. Always work with your healthcare provider.
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