Tirzepatide units calculator
Your prescribed dose, in units on a U-100 syringe, for a liquid vial, a powder you mix, or a branded single-dose or multi-dose vial.
Filled from the calculator. Add your next step and print. Nothing is sent or stored.
How to use the calculator
- Choose your vial: a liquid vial (compounded), a powder you mix, or a branded single-dose or multi-dose vial.
- Enter the dose your prescriber set, in milligrams.
- For a liquid vial, enter the concentration printed on the label in mg/mL. For a powder, enter the milligrams in the vial and the water you add.
- Read the units to draw on a U-100 insulin syringe, where 100 units is 1 mL.
The formula
units = dose in mg ÷ concentration in mg/mL × 100
5 mg from a 10 mg/mL vial is 5 ÷ 10 × 100 = 50 units, or 0.5 mL. The same 5 mg from a 20 mg/mL vial is 25 units. The dose did not change; the vial did, which is why the concentration on every new vial needs checking.
Powder vials
A powder has no concentration until water is added. The concentration is the milligrams in the vial divided by the millilitres of water: 10 mg mixed with 2 mL makes 5 mg/mL, so 2.5 mg is 50 units. The calculator does this step for you and shows how many doses the vial holds.
Branded vials and pens
A branded single-dose vial is always 0.5 mL (50 units) and a multi-dose vial 0.6 mL (60 units), at every strength; the concentration rises with the dose instead1,2. The single-dose pen and the KwikPen deliver the dose themselves and need no syringe. See Zepbound dosing for every presentation.
Frequently asked questions
How do you calculate tirzepatide units?
Divide the dose in mg by the concentration in mg/mL and multiply by 100. On a U-100 syringe, 100 units is 1 mL.
How many units is 2.5 mg of tirzepatide?
25 units from a 10 mg/mL vial, 50 units from a 5 mg/mL vial, and 50 units from a branded single-dose vial. Check the concentration on your own label.
How much water do you add to a tirzepatide powder vial?
That is set by whoever supplied the vial. The calculator works out the concentration and units from the milligrams in the vial and the water you add.
Can I use this for a Zepbound KwikPen?
No syringe is used with a KwikPen or single-dose pen; the pen delivers the dose. The calculator is for vials.