Tirzepatide Dosing Calculator
Pick your vial size, enter your prescribed dose in mg, and choose your syringe. You get how much bacteriostatic water to add and the exact units to draw.
For tirzepatide that comes as a powder. Mounjaro and Zepbound pens, and Zepbound single-dose vials, are already measured and need no mixing.
Step 1 · Vial strength
This is printed on your vial or the product listing. Common amounts are 10mg, 20mg, 30mg, and 60mg.
How it works
- Enter your vial strength: the mg printed on the vial (10, 20, 30, and 60 mg are common).
- Enter your prescribed dose per injection in mg.
- Pick your syringe: 100-unit (1 mL) or 30-unit (0.3 mL).
- Read how much BAC water to add, how many units to draw, and how many doses the vial holds.
Frequently asked questions
How much BAC water do I add to a 10 mg tirzepatide vial?
There's no single right amount; it sets the concentration. 1 mL of BAC water makes 10 mg/mL, so each unit on a U-100 syringe is 0.1 mg. 2 mL makes 5 mg/mL, so each unit is 0.05 mg. More water means more units per dose, which is easier to measure accurately. The calculator suggests an amount and lets you change it.
How many units is 2.5 mg of tirzepatide?
At 10 mg/mL (a 10 mg vial with 1 mL of water), 2.5 mg is 25 units. At 5 mg/mL (10 mg with 2 mL), it's 50 units. The units always depend on how much water went into the vial.
How many mg is 40 units of tirzepatide?
Multiply the units by 0.01 to get mL, then by your concentration. At 10 mg/mL, 40 units is 0.4 mL, or 4 mg. At 5 mg/mL, 40 units is 2 mg.
What's the standard tirzepatide dose schedule?
The labeled schedule for Mounjaro and Zepbound starts at 2.5 mg once weekly and increases in 2.5 mg steps no sooner than every 4 weeks, up to a maximum of 15 mg. Your prescriber sets your dose and when to change it.
Track your protocol in DoneDose
DoneDose logs your doses, tracks serum levels over time, and reminds you when to inject next.
Related calculators & guides
This calculator is for informational purposes. Consult your prescribing provider for medical advice specific to your protocol. DoneDose does not provide medical advice.