Dosage calculator

What is actually in those units?

Someone told you a mark to draw to and left it there. Enter that number of units alongside the concentration printed on your vial, and this gives you the dose in milligrams, where it falls on the branded ladder, and whether it is above what the FDA label allows.

Select your drug

Vial concentration (mg/mL)

Read this off the vial. Every compounded vial has the concentration printed on it.

Units drawn on the syringe

units

You are injecting

1mg

Volume drawn

0.400mL

FDA max weekly dose

2.4mg (Wegovy)

Equivalent branded dose

1 mg — Wegovy escalation dose (weeks 9-12)

The vial label is the authority here. One reading on the syringe means different milligrams at every concentration. If the vial does not say what you picked above, work it out again before you draw.

Quick reference: units → mg at common concentrations

Semaglutide doses at common compounded concentrations.

Units	@ 2.5 mg/mL	@ 5 mg/mL	@ 10 mg/mL
5 units	0.13 mg	0.25 mg	0.5 mg
10 units	0.25 mg	0.5 mg	1 mg
15 units	0.38 mg	0.75 mg	1.5 mg
20 units	0.5 mg	1 mg	2 mg
25 units	0.63 mg	1.25 mg	2.5 mg(above max)
30 units	0.75 mg	1.5 mg	3 mg(above max)
40 units	1 mg	2 mg	4 mg(above max)
50 units	1.25 mg	2.5 mg(above max)	5 mg(above max)
60 units	1.5 mg	3 mg(above max)	6 mg(above max)
80 units	2 mg	4 mg(above max)	8 mg(above max)
100 units	2.5 mg(above max)	5 mg(above max)	1 mg(above max)

How the reverse calculation works

Compounded GLP-1s come with a U-100 syringe, which is calibrated so that 100 units fill 1 mL [1]. Given the units drawn and the concentration on the vial in mg/mL, the dose follows:

mg = (units × concentration in mg/mL) ÷ 100

Worked through: 40 units taken from a semaglutide vial at 2.5 mg/mL gives

mg = (40 × 2.5) ÷ 100 = 1.0 mg

On the Wegovy ladder, 1.0 mg is the step taken in weeks 9 to 12 [2]. Take those same 40 units from a 5 mg/mL vial instead and you have injected 2.0 mg — near enough twice as much. The concentration is the whole difference, which is why it has to be read every time.

When to use this tool

You were told to draw to 25 units and nobody said what that amounts to.
A new pharmacy has sent a vial at a different strength, and you want to know whether the unit count you have been using still delivers the same milligrams.
You want to place your dose against the titration schedule printed on the Wegovy or Zepbound label.

FDA maximum weekly doses

Anything above the weekly ceiling on the label gets flagged for the drug you pick:

Semaglutide. Wegovy tops out at a maintenance dose of 2.4 mg a week [2]. Ozempic, prescribed for type 2 diabetes, stops lower, at 2.0 mg [3].
Tirzepatide. Both Zepbound and Mounjaro reach a maintenance ceiling of 15 mg a week [4, 5].

Landing above one of those ceilings does not by itself mean the prescription is a mistake. Some prescribers do go past the labeled maximum, off-label and deliberately. It does mean the subject is worth raising with whoever wrote it.

Important safety disclaimer

This page does arithmetic and gives no medical advice. Read the concentration off the vial before drawing anything. Where what you see here and what you were told do not agree, do not inject. Call the prescriber or the compounding pharmacy and settle it first.

References

1.Becton, Dickinson and Company (BD). BD Ultra-Fine Insulin Syringes — Product Specifications and U-100 Standard. BD Diabetes Care Product Documentation. 2024. https://www.bd.com/en-us/products/diabetes/diabetes-injection/insulin-syringes
2.Novo Nordisk Inc. WEGOVY (semaglutide) injection — US Prescribing Information. FDA Approved Labeling. 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/215256s026lbl.pdf
3.Novo Nordisk Inc. OZEMPIC (semaglutide) injection — US Prescribing Information. FDA Approved Labeling. 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/209637s035,209637s037lbl.pdf
4.Eli Lilly and Company. ZEPBOUND (tirzepatide) injection — US Prescribing Information. FDA Approved Labeling. 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/217806s002lbl.pdf
5.Eli Lilly and Company. MOUNJARO (tirzepatide) injection — US Prescribing Information. FDA Approved Labeling. 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/215866s039lbl.pdf
6.U.S. Food and Drug Administration. Compounded Drug Products — 503A and 503B Outsourcing Facility Information for Patients. FDA Drug Compounding Resources. 2024. https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers

Related tools and research

GLP-1 unit ↔ mg converter — the same conversion both ways, with lookup tables.
GLP-1 split dose calculator — dividing one weekly dose across two or three injections.
GLP-1 vial transition calculator — the new reading after a vial changes strength.
GLP-1 dose plotter — how each rung of the ladder accumulates toward steady state.
GLP-1 reconstitution calculator — how much bacteriostatic water a dry vial needs.
Compounded semaglutide bioequivalence — the testing a compounding pharmacy actually owes you.

Ready to start? GLP-1 providers we have vetted

Telehealth providers, vetted by us, prescribing GLP-1 online.

Vetted by our editors · no insurance required

Some of the links on this page earn us money. If you sign up with a provider after following one, that provider may pay GLP Watchdog a commission. Learn more

6.7