How the Tirzepatide calculator works
Licensed products are single-dose pens and single-dose vials, already in solution. Multi-dose vials are either a ready-mixed solution labelled in mg/mL or a lyophilized powder labelled in milligrams. The quick-fill buttons in the calculator are the vial sizes Tirzepatide is commonly labelled in (5 mg, 10 mg, 15 mg and 30 mg). If yours is different, type it in.
Amounts of Tirzepatide are usually written in milligrams (mg), so the calculator opens in mg.
If your vial is a ready-mixed solution, nothing is reconstituted. Enter any vial size and water volume that give the labelled concentration, for example 10 mg and 1 mL for a 10 mg/mL solution.
For a field-by-field walkthrough and a guide to syringe types, see the main peptide calculator.
Tirzepatide concentration table
Each labelled vial size at the same three round water volumes used across this site. It shows how the arithmetic behaves and is not a suggestion of what to use.
| Vial | Water added | Concentration | Each mark holds |
|---|---|---|---|
| 5 mg vial | 1 mL | 5 mg/mL | 0.5 mg per 10 units |
| 5 mg vial | 2 mL | 2.5 mg/mL | 0.25 mg per 10 units |
| 5 mg vial | 3 mL | 1.67 mg/mL | 0.167 mg per 10 units |
| 10 mg vial | 1 mL | 10 mg/mL | 1 mg per 10 units |
| 10 mg vial | 2 mL | 5 mg/mL | 0.5 mg per 10 units |
| 10 mg vial | 3 mL | 3.33 mg/mL | 0.333 mg per 10 units |
| 15 mg vial | 1 mL | 15 mg/mL | 1.5 mg per 10 units |
| 15 mg vial | 2 mL | 7.5 mg/mL | 0.75 mg per 10 units |
| 15 mg vial | 3 mL | 5 mg/mL | 0.5 mg per 10 units |
| 30 mg vial | 1 mL | 30 mg/mL | 3 mg per 10 units |
| 30 mg vial | 2 mL | 15 mg/mL | 1.5 mg per 10 units |
| 30 mg vial | 3 mL | 10 mg/mL | 1 mg per 10 units |
Every row for a given vial holds the same total. To compare volumes for a specific reading, use the BAC water calculator.
The formula, step by step
The “Try example numbers” button uses one fixed rule on every page: the smallest labelled vial, 2 mL of water, and whatever amount lands on the 10-unit mark. The amount is a by-product of that rule and not a typical or suggested Tirzepatide dose.
- Concentration: 5 mg ÷ 2 mL = 2.5 mg/mL.
- The 10-unit mark is 10 ÷ 100 = 0.1 mL, which holds 0.1 × 2.5 = 0.25 mg.
- Run it forwards to check: 0.25 mg ÷ 2.5 mg/mL = 0.1 mL, and 0.1 × 100 = 10 units.
Tirzepatide: general reference
General educational reference for research purposes only. None of it is a recommendation, none of it is medical advice, and none of it is used by the calculator, which works only on the numbers you enter.
Tirzepatide is a single molecule that activates two receptors, GIP and GLP-1. It was developed by Eli Lilly and is an approved prescription medicine, sold as Mounjaro and Zepbound.
The FDA approved Mounjaro in May 2022 and Zepbound in November 2023.
Both brands come as single-dose pre-filled pens. Since 2024 Zepbound has also been sold in single-dose vials, each holding one dose that is already in solution, so nothing is reconstituted.
During the shortage, compounded tirzepatide was widely sold in multi-dose vials, which is where the unit arithmetic on this page applies. The FDA took tirzepatide off its shortage list in October 2024 and confirmed the decision that December, which ended broad compounding.
- Class
- Dual GIP and GLP-1 receptor agonist, approved medicine
- Group
- GLP-1 family
- Also known as
- Mounjaro, Zepbound
- Molecular weight
- About 4,814 Da
- Half-life
- About 5 days. The FDA-approved prescribing information gives an elimination half-life of approximately 5 days.
- Regulatory status
- Approved medicine. Tirzepatide is approved by the FDA and the EMA as a prescription medicine. The licensed pens and single-dose vials are pre-measured and need no calculator. Compounding is now limited to narrow, patient-specific cases.
- Labelled vial sizes
- 5 mg, 10 mg, 15 mg and 30 mg
Arithmetic slips to watch for with Tirzepatide
A single-dose vial is not a multi-dose vial
A licensed single-dose vial holds one pre-measured dose, so there is nothing to work out. The arithmetic on this page is only for multi-dose vials, where the amount drawn up depends on the concentration.
Large vials mean high concentrations
Tirzepatide vials run up to 30 mg. With 1 mL of water that is 30 mg/mL, so 10 units already holds 3 mg. The more concentrated the vial, the more a misreading of a single unit matters.
Units are not milligrams
Units measure volume. The same 10 units holds 0.5 mg at 5 mg/mL, 1 mg at 10 mg/mL and 2 mg at 20 mg/mL. A unit count is only correct for the concentration it was worked out for.
What this page does not do
The calculator performs mathematical conversions only. It does not recommend, suggest or verify any Tirzepatide dose or schedule, it does not say how much water to add, and it does not say what Tirzepatide is for, whether it is safe, or whether it is legal where you live. It is not medical advice, diagnosis or treatment, and Peptrack does not sell, supply or endorse any substance.
Always confirm measurements with a licensed healthcare provider or pharmacist. See the full disclaimer.
Mounjaro and Zepbound are trademarks of Eli Lilly and Company. Peptrack is not affiliated with, or endorsed by, Eli Lilly or any other manufacturer.
Sources
- Zepbound (tirzepatide) prescribing information, Eli Lilly
- FDA declaratory order: resolution of the tirzepatide shortage (December 2024)
- FDA: policies for compounders as national GLP-1 supply stabilizes
Facts last checked: September 2026. Regulatory status changes, so check the regulator’s own pages for the current position.
