Dose calculator · semaglutide

Semaglutide Dosage Calculator: mg to Units (U⁠-⁠100 Syringe)

To turn a semaglutide dose into units, divide the dose in mg by the strength on your vial (mg per mL). That gives you mL. Multiply by 100 to get units on a U-100 insulin syringe. For example, 0.25 mg from a 2.5 mg/mL vial is 0.10 mL, or 10 units on a U-100 insulin syringe. A U-40 or other syringe would give a different draw. This is only math. It does not choose your dose.

Last updated September 30, 2026

Sold as: Ozempic, Wegovy
Standard doses: 0.25 mg to 2.4 mg

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Semaglutide calculator

U-100 syringe: 100 units = 1 mL

Step 1 of 425%

What kind of vial do you have?

Powder: you add liquid to it before the first dose.Liquid: the label shows a strength in mg/mL.

The math in plain language

The formula

Units to draw = dose (mg) ÷ vial strength (mg/mL) × 100. That works on any U-100 insulin syringe, where 100 units = 1 mL.

Example for semaglutide:0.25 mg from a 2.5 mg/mL vial → 0.25 ÷ 2.5 × 100 = 10 units (0.10 mL).

Mixing a powder vial? Strength = mg in the vial ÷ mL of water added. 5 mg + 2 mL = 2.5 mg/mL. The vial label's strength is what decides the answer.

How to read your result

The units shown here measure liquid on a U-100 syringe. They are not a dose recommendation. Syringe makers name the thin black line, the top of the plunger, or the plunger tip as the reference for the dose line. We read all three as the edge of the plunger closest to the needle. Learn how to read an insulin syringe.

Check the strength printed on your vial before you use any of these numbers. See how units, mL and mg differ and compare insulin syringe sizes.

If your medicine came from a pharmacy vial

Compounded semaglutide: what the FDA says

“Compounded” means a pharmacy made its own version instead of the brand-name product. If your semaglutide came from a pharmacy in a vial, here is what matters most:

Throw the vial away 28 days after you first use it, even if its label says it lasts longer.
Use a new sterile needle and syringe for every dose.
The FDA has hundreds of reports of side effects and other problems with compounded versions, some involving doses higher than the label’s schedule.
The shortage is over. The FDA says pharmacies may no longer regularly make copies of the brand-name medicine.

The details from the FDA

The semaglutide shortage was resolved on February 21, 2025. The FDA then gave compounders a wind-down period, when it held off on enforcing its rules against compounded (pharmacy-made) copies. That period ended April 22, 2025 for 503A pharmacies (standard compounding pharmacies) and May 22, 2025 for 503B outsourcing facilities (larger-scale compounders). The FDA says 503A pharmacies may not regularly compound a drug that is “essentially a copy” of one sold commercially. Adding vitamin B12 does not get around that rule when the strength is within 10%. The FDA also says 503B outsourcing facilities may not use semaglutide as a raw drug ingredient (API), because it is not on the 503B bulks list or a shortage list. As of May 31, 2026, the FDA had 990 reports of side effects or other problems (adverse events) with compounded semaglutide and more than 730 with compounded tirzepatide.

If a pharmacy gave you semaglutide in a vial, find the strength printed on that vial before you use any of these numbers.

Brand-name vs compounded: what is different about the vial?

The brand-name semaglutide forms listed here are Ozempic and Wegovy pens, Ozempic and Wegovy single-dose syringes, and Wegovy tablets.

A brand-name label fixes the labeled dose and the device or container used to deliver it.

Compounded means a pharmacy made its own version instead of the brand-name product. Its strength is the mg/mL printed on that vial's label, so the units depend on your vial.

The FDA has reported dosing errors with compounded semaglutide when people confused units, mL, and vial strength.

Reference table

Semaglutide: mg to units

Find your dose in the left column. Each of the other columns is an example vial strength.

If a pharmacy gave you semaglutide in a vial, find the mg/mL on the vial label. Units are for a U-100 insulin syringe (1 unit is 0.01 mL). Always check the lines on your own syringe.
Dose	1 mg/mL	2 mg/mL	2.5 mg/mL	5 mg/mL	10 mg/mL
0.25 mg	25	12.5	10	5	2.5
0.5 mg	50	25	20	10	5
1 mg	100	50	40	20	10
1.7 mg	—	85	68	34	17
2 mg	—	100	80	40	20
2.4 mg	—	—	96	48	24
To measure a half unit, you need a syringe with ½-unit lines (see syringe sizes). Whether you can read an amount depends on the lines on your own syringe.

A dash (—) means the amount is more than a 1 mL syringe holds at this strength. The table shows exact units. Whether you can measure an amount depends on the lines on your own syringe. This table is only math, not dose instructions.

The Wegovy label also lists a 7.2 mg dose for some adults who have taken 2.4 mg for at least 4 weeks and need more weight loss, under a prescriber's care. It is sold only as the pre-filled, single-dose Wegovy HD pen, so it is not drawn from a vial and is not in this table. See Wegovy pens

How the FDA labels step up the dose

Ozempic and Wegovy each have their own schedule on their label. We show them for reference only. The two products differ in how the dose goes up, which dose you stay on, and what to do if you miss a dose.

For reference only. The product label and your prescriber decide the dose.
Step	Dose (mg)	What the label says
Ozempic injection label
Starting dose	0.25	Once a week for 4 weeks.
After at least 4 weeks	0.5	Once a week, after at least 4 weeks at 0.25 mg.
Only if needed	1	After at least 4 weeks at 0.5 mg, if blood sugar needs more control. When Ozempic is used for chronic kidney disease, 1 mg is the dose to stay on (the maintenance dose).
Only if needed	2	After at least 4 weeks at 1 mg, if blood sugar needs more control.
Wegovy injection label
Weeks 1–4	0.25	Starting dose, once a week.
Weeks 5–8	0.5	Once a week.
Weeks 9–12	1	Once a week.
Weeks 13–16	1.7	Once a week. For weight loss in adults, 1.7 mg can also be the dose to stay on.
Dose to stay on (maintenance)	2.4	The recommended dose to stay on for adults using Wegovy for weight loss. Other uses of Wegovy can differ.
Optional highest dose	7.2	After at least 4 weeks at 2.4 mg, if more weight loss is medically needed.

Key facts

Where to inject, what to do after a missed dose, and how to store it, as the label puts it.

Injection sites

The Ozempic and Wegovy injection labels list the stomach area (abdomen), thigh, or upper arm. Use a different spot each time you inject.

Missed dose

Ozempic: If it has been 5 days or less, take the missed dose as soon as you can. If more than 5 days have passed, skip it and go back to your usual day.

Wegovy injection: If your next dose is more than 2 days away, take the missed dose as soon as you can. If it is less than 2 days away, skip the missed dose.

Wegovy tablets: Skip the missed dose. Take your next dose the following day.

Storage

Keep Ozempic pens in the fridge before first use. After first use, a pen can be kept for 56 days if you store it the way the label says.

Keep Wegovy single-dose pens and syringes in the fridge. Before the cap comes off, they can be kept at 8–30 °C (46–86 °F) for up to 28 days.

Keep Wegovy FlexTouch in the fridge before first use. After first use, it can be kept for 56 days if you store it the way the label says.

Common mistakes

The FDA has seen people take far more than they meant to when drawing compounded semaglutide from a vial.

Read the guide to common dosing mistakes

If you are not sure about the strength, the units or the lines on your syringe, stop and check the label with your healthcare provider or pharmacist.

Common questions

How do I turn mg into units?

First check the strength printed on the vial, in mg per mL. Divide your prescribed dose in mg by that strength to get mL. Then multiply by 100 to get units on a U-100 insulin syringe. For example, a vial with 5 mg in 2 mL has a strength of 2.5 mg/mL (5 ÷ 2). So 0.25 mg is 0.10 mL, which is 10 units.

Sources: Technical Data Sheet – Insulin Syringes

What does 1 unit mean on a U-100 syringe?

U-100 means 100 units fill 1 mL, so 1 unit is 0.01 mL.

Sources: Technical Data Sheet – Insulin Syringes, ISO 8537:2016, sterile single-use insulin syringes

Why can the same mg dose be a different number of units?

Units measure how much liquid you draw, not how much medicine is in it. When the strength of the vial changes, the amount of liquid for the same dose changes too.

Sources: Technical Data Sheet – Insulin Syringes

Can I use the units from a different vial?

No. A units number from one strength does not carry over to another. Work it out again from the strength printed on the vial you are using, and check it with your healthcare provider or pharmacist.

Sources: FDA alerts about dosing errors with compounded semaglutide

Which plunger edge is the reference for the dose line?

Syringe makers name the thin black line, the top of the plunger, or the plunger tip as the reference. We read all three as the edge of the plunger closest to the needle.

Sources: Injection technique guide, Getting Started booklet, SafetyGlide Insulin Syringes quick reference guide, Zepbound single-dose vial Instructions for Use

Does the calculator choose my semaglutide dose?

No. It only does the math for the dose and strength you enter. The labels describe dose schedules, but your prescriber sets your dose.

Sources: Ozempic (semaglutide) US Prescribing Information, Wegovy (semaglutide) US Prescribing Information

Other calculators, quick answers for common doses, and the how-to guides.

All guides

Double-check the math every time

It takes about 20 seconds. Have your prescription and your vial in front of you while you check it.

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Sources

The medical and device facts on this page come from these sources. Each entry shows the date we accessed it.

01 Ozempic (semaglutide) US Prescribing Information · Novo Nordisk, 05/2026. Accessed 2026-09-28.
02 Wegovy (semaglutide) US Prescribing Information · Novo Nordisk, 06/2026. Accessed 2026-09-28.
03 Technical Data Sheet – Insulin Syringes · embecta, Rev B, 12/2025. Accessed 2026-09-28.
06 SafetyGlide Insulin Syringes quick reference guide · embecta. Accessed 2026-09-28.
07 Zepbound single-dose vial Instructions for Use · Eli Lilly, 04/2026. Accessed 2026-09-28.
08 ISO 8537:2016, sterile single-use insulin syringes · International Organization for Standardization, 2016. Accessed 2026-09-28.
09 FDA alerts about dosing errors with compounded semaglutide · U.S. Food and Drug Administration, 07/26/2024. Accessed 2026-09-28.
10 FDA clarifies policies for compounders as GLP-1 supply stabilizes · U.S. Food and Drug Administration, 04/01/2026. Accessed 2026-09-28.
11 FDA's concerns with unapproved GLP-1 drugs used for weight loss · U.S. Food and Drug Administration, 10/01/2026. Accessed 2026-10-01.

Medically reviewed by Ashley Alexis, NDLast reviewed September 30, 2026How we review