FREE SEMAGLUTIDE CALCULATOR
Semaglutide calculator
Reconstitution and syringe units.
Enter your semaglutide vial size, the water you added and the amount from your instructions. See the units on a U-100 insulin syringe, instantly.
A math tool, not medical advice. It calculates from the values you enter and does not choose a dose.
SEMAGLUTIDE RECONSTITUTION
One semaglutide vial.
Two numbers to know.
The vial amount and the water you add set the concentration. For a 5 mg vial with 2 mL of water, the concentration is 5 ÷ 2 = 2.5 mg/mL, so each unit on a U-100 syringe holds 25 mcg. The chart below covers the other vial sizes.
- Vial sizes on this page
- 2, 3, 5 and 10 mg
- Concentration with 1 to 3 mL of water
- 0.667 to 10 mg/mL
- Amount in each unit
- 6.67 to 100 mcg
- Amount unit
- Starts in mg; switch to mcg if your instructions use it
Working with another peptide? Use the general peptide calculator.
HOW IT WORKS
Three numbers.
One mark on the syringe.
Vial amount
How much peptide the vial holds, printed on the label in mg.
Water added
How much bacteriostatic water you mixed in, in mL. Together with the vial amount this sets the concentration.
Your dose
The amount from your instructions, in mcg or mg. The calculator turns it into syringe units.
Concentration = vial amount ÷ water
Units = dose ÷ concentration × 100
Example: 5 mg in 2 mL is 2.5 mg/mL, so each unit holds 25 mcg. Units to draw = your amount in mcg ÷ 25. How rounding works →
RECONSTITUTION CHART
How much is in
each unit?
Concentration for common vial sizes and water volumes, and how much peptide each unit on a U-100 syringe holds.
| Vial | 1 mL water | 2 mL water | 3 mL water |
|---|---|---|---|
| 2 mg | 20 mcg2 mg/mL | 10 mcg1 mg/mL | 6.67 mcg0.667 mg/mL |
| 3 mg | 30 mcg3 mg/mL | 15 mcg1.5 mg/mL | 10 mcg1 mg/mL |
| 5 mg | 50 mcg5 mg/mL | 25 mcg2.5 mg/mL | 16.67 mcg1.667 mg/mL |
| 10 mg | 100 mcg10 mg/mL | 50 mcg5 mg/mL | 33.33 mcg3.333 mg/mL |
Bold: mcg in each unit. Below it: concentration. 1 unit = 0.01 mL on a U-100 syringe. Values are arithmetic, not recommendations.
Printable chart and formulas → · Convert mg to syringe units →
CALCULATORS BY PEPTIDE
Same math,
your vial sizes.
FOR THE NEXT TIME
This page forgets.
Dosii remembers.
Use this page for a quick check. If you calculate the same vial every week, the Dosii iPhone app keeps it ready.
No account. No subscription. Your numbers stay on your iPhone.
This page
- One calculation at a time
- 100-unit syringe
- Clears when you leave
Dosii app
- Saved calculations, named and ready
- Water suggestions for clean marks
- 30, 50 and 100-unit syringes
- Cost per dose
- Works offline, stays on your iPhone
QUESTIONS
Good to know.
How much water should I add to a 5 mg semaglutide vial?
Follow the instructions for your product. Water changes the concentration, not the amount of semaglutide in the vial. For a 5 mg vial: with 1 mL, each unit holds 50 mcg; with 2 mL, 25 mcg; with 3 mL, 16.67 mcg. More water means more units for the same amount.
What if my semaglutide is already mixed?
Use the concentration on the label. Enter the mg/mL figure as the vial amount and 1 mL as the water; if the label is in mcg/mL, divide by 1,000 first. The units shown are then correct for that concentration. The doses-in-vial count and the vial-size warnings assume a whole 1 mL vial, so they do not apply in this mode.
Does the calculator work for any semaglutide vial size?
Yes. The quick picks are shortcuts for vial sizes people often enter; type any amount in mg. Choose mcg or mg to match how your instructions write the amount.
How many units should I draw?
This calculator converts the numbers you enter into syringe units: your dose divided by the concentration, times 100 on a U-100 syringe. It checks the arithmetic, not the dose. Use the amount from your own instructions.
What is a unit on an insulin syringe?
On a U-100 syringe, 100 units equal 1 mL, so one unit is 0.01 mL. 30-, 50- and 100-unit syringes all use this same scale. They differ in how much they hold, not in what a unit means.
How does the amount of water change the result?
Water changes the concentration, not the amount of peptide in the vial. Adding more water spreads the same peptide through more liquid, so the same dose takes more units. The reconstitution chart on this page shows how common water volumes change the amount in each unit.
Why do peptide calculators sometimes disagree?
Usually because of units (mg versus mcg) or rounding. This calculator keeps full precision internally and rounds only the displayed result to the nearest half unit. Open “Show the math” to check each step.
Does this calculator save my numbers?
No. The values you enter stay in this browser tab and disappear when you leave or reload; they are never stored or sent. Separately, the website counts visits, App Store clicks and that the calculator was used, without the numbers you enter. If you want to keep a calculation and reuse it, the Dosii iPhone app saves it on your device. Privacy details.
Dosii explains terminology and calculates from the values you enter. It does not choose a dose or verify a product. Follow product-specific instructions and guidance from a qualified healthcare professional.