Tool
Semaglutide dosage calculator
Enter a semaglutide vial's mg amount, the diluent you added, and a dose - get the concentration, the volume to draw, and insulin-syringe units. Arithmetic only; it does not know your dose or your vial.
Guides:semaglutide dosage (FDA schedules)·semaglutide overview
Your vial
Printed on the vial. There is no standard size - enter what yours says.
This changes how much you draw - never how many doses the vial holds.
100 units per mL. 1 unit = 0.01 mL. This is what almost every insulin syringe sold is, in every barrel size.
Capacity only. A 1 mL U-100 syringe holds 100 units - the scale decides that, not the barrel.
Draw this much
= 0.1 mL on a 1 mL U-100 syringe
- Concentration
- 2,500 mcg/mL
- Exact volume
- 0.1 mL
- Dose you actually get
- 250 mcg
- Doses per vial(unaffected by water volume)
- 20
The 5 mg vial / 0.25 mg dose shown above is only an example to demonstrate the arithmetic (0.25 mg is the FDA-approved starting dose for the approved pens) - it is not a recommendation. Replace every field with your own vial's actual numbers. Results update in the address bar so a calculation is shareable; nothing is stored.
The actual semaglutide dose
The dosing schedule that has gone through FDA review differs by brand: Wegovy titrates over 16 weeks to a 2.4 mg (or 1.7 mg) weekly maintenance dose for weight management, and Ozempic titrates over a shorter run to a maintenance dose between 0.5 mg and 2 mg weekly for type 2 diabetes. Both start at 0.25 mg weekly. The current Wegovy label also allows patients who have tolerated 2.4 mg for at least 4 weeks and need additional weight reduction to increase to a maximum of 7.2 mg once weekly. The full schedules, missed-dose rules and who should not use it are on thesemaglutide dosage page. Background on the drug itself - mechanism, approval, boxed warning - is on themain semaglutide page.
This calculator answers a different question: once you know a dose in mg, how much volume does that come to in a given vial, and how many syringe units is that. It does not set the dose itself.
Common questions
Is this the FDA-approved semaglutide dose?
The 0.25 mg starting dose preset here is the FDA-approved starting dose used by both Wegovy and Ozempic. This calculator itself does not know your dose - it only converts a vial size, diluent volume and dose into a volume to draw and syringe units. See the semaglutide dosage page for the full approved titration schedules by brand.
Does this calculator work for a compounded semaglutide vial?
It will do the arithmetic for any vial size and diluent volume you type in. It has no way to verify what is actually in a compounded vial, and a compounded vial has not gone through the review that set the approved Wegovy or Ozempic schedules.
What is a common semaglutide vial size?
Vial sizes vary by supplier and are not standardized the way the approved pen doses are. The 5 mg example preset on this page is only a starting point to show the arithmetic - type in the actual mg amount printed on your own vial label before drawing anything.
How much semaglutide do I draw for 0.25 mg?
That depends entirely on the concentration after reconstitution, which depends on the vial size and how much diluent was added - there is no single answer. Enter the vial's mg amount and diluent volume into the calculator above and it works out the volume and syringe units for whatever dose you enter.
Can I use an insulin syringe for semaglutide?
People commonly measure small-volume injections with insulin syringes marked in units, which is what the syringe-scale option in this calculator converts to. A U-100 syringe is 100 units per mL regardless of barrel size (0.3, 0.5 or 1 mL) - see the peptide calculator page for why "U-50" is not a real scale.
Is this medical advice?
No. It performs arithmetic on numbers you type - it does not know what is in your vial, whether a dose is appropriate, or whether you should be using semaglutide at all. Follow your prescriber and the product label for an approved pen; a compounded or research vial carries none of that review.