Free tool
Tirzepatide Dosage Calculator
After reconstituting a tirzepatide vial, work out the exact volume to draw and the units on your syringe. Enter your dose, the vial amount, and the bacteriostatic water you added.
Example values shown; enter your own. For calculation and organization only, not medical advice.
How to use the tirzepatide calculator
- Desired dose: the dose you intend to draw, in mg or mcg.
- Vial amount: the total tirzepatide in the vial (printed on the label), in mg.
- Bacteriostatic water added: the volume of water you used to reconstitute, in mL.
- Syringe: match it to the insulin syringe you'll use (U-100 is most common).
The calculator shows the volume to draw in mL plus the equivalent syringe units, updating as you type.
The math behind it
Volume to draw (mL) = desired dose (mg) ÷ concentration (mg/mL)
Units = volume (mL) × 100 (for a U-100 syringe)
For a full walkthrough, see how to calculate peptide dosage.
Reconstituting tirzepatide
Tirzepatide is often supplied as a freeze-dried powder that you reconstitute with bacteriostatic water before use. The amount of water you add sets your concentration, which is why the calculator asks for it. See how to reconstitute a peptide and how much bacteriostatic water to add.
Choosing your syringe
U-100 syringes read 100 units per mL, U-50 read 50 per mL, and U-40 read 40 per mL, so the same volume shows a different number of units on each. Always set the calculator to the syringe in your hand. Details in syringe units explained.
Tirzepatide is a prescription medication. This calculator performs dosage math only and is not medical advice, a recommendation, or a prescription. It does not suggest any dose. Always follow your prescriber's instructions and consult a qualified clinician before starting, changing, or stopping any medication.