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This peptide calculator for tirzepatide turns the milligram dose on your prescription into the number of units to draw on a U-100 insulin syringe. It only does the math. Your prescriber decides the dose, and your pharmacy label tells you the vial size and how much diluent went in.
Step 1: Pick your syringe. Choose the size you actually have: 0.3 mL (30 units), 0.5 mL (50 units), or 1 mL (100 units). If the result is bigger than your syringe holds, the calculator will flag it.
Step 2: Enter your vial size. Use the milligrams printed on the vial label, such as 10 mg. Tap Custom if yours isn't listed.
Step 3: Enter the diluent volume. This is the bacteriostatic water (or other diluent) that was added to the powder. If your pharmacy sent the vial already mixed, use the concentration on the label instead: a vial labelled 5 mg/mL is the same as 10 mg in 2 mL.
Step 4: Enter your prescribed dose in mg. The presets are shortcuts for common numbers, not recommendations. Always use the dose your prescriber gave you.
The result shows the units to draw, the concentration in mg/mL, and the volume in mL. Write the concentration on your vial so you never have to guess next week.
Units on an insulin syringe measure volume, not drug. On a U-100 syringe, 100 units is always 1 mL. How much tirzepatide sits in those units depends on your vial's concentration, so this table shows the same syringe readings at three common concentrations.
At 5 mg/mL, 10 units holds 0.5 mg and 1 mg is 20 units. At 10 mg/mL, the same 10 units holds 1 mg and 1 mg is only 10 units. That's why you can't carry a unit count over when your vial, pharmacy, or diluent volume changes. The FDA has reported people taking several times their intended dose of compounded GLP-1s because of exactly this mix-up between mg, mL, and units (FDA alert).
Mounjaro and Zepbound, the FDA-approved tirzepatide products, come as ready-to-use pens and vials, per the Zepbound label. Follow the instructions that came with them. This calculator is for compounded tirzepatide in a vial, which is not FDA-approved and isn't reviewed by the FDA for safety or quality. Get it only through a licensed prescriber and pharmacy, never from sellers marketing "research use only" products.
For the mixing process itself, including a full vial-by-vial chart and storage tips, see our guide on how to reconstitute tirzepatide. If you use several peptides, the general peptide calculator works for any of them.
Once you know your number, PeptideKit can remember it for you. It schedules your weekly injection, reminds you when it's due, and keeps a log of every dose and side effect to share with your prescriber.
Divide your dose in mg by your vial's concentration in mg/mL to get the volume in mL, then multiply by 100 for units on a U-100 syringe. The concentration is the vial's mg divided by the mL of diluent added. The calculator above does all three steps for you.
It depends on the concentration. At 5 mg/mL, 1 mg is 20 units. At 10 mg/mL, 1 mg is 10 units. Check the concentration on your vial label before converting.
10 units on a U-100 syringe is always 0.1 mL. At 5 mg/mL that's 0.5 mg of tirzepatide, and at 10 mg/mL it's 1 mg. The conversion table above covers other readings.
No. Branded pens deliver a fixed dose and don't use syringe units. This calculator is for tirzepatide drawn from a vial with an insulin syringe.
Don't try to eyeball it. Ask your pharmacy whether you should use a larger syringe. Never change the dose or the diluent volume without your prescriber or pharmacist.
Always consult with qualified healthcare professionals before starting any peptide therapy protocol. This information is for educational purposes only and does not constitute medical advice.
Tirzepatide Peptide Calculator
Enter your tirzepatide vial size, how much diluent was added, and the dose your prescriber gave you in mg. The calculator shows how many units to draw on a U-100 insulin syringe.
Calculated Dosage
For a dose of 2.5 mg, pull the syringe to:
50.0 units
Concentration
5.00 mg/ml
Volume
0.500 ml
Syringe
50 units = 0.5ml
Syringe
Peptide Vial Quantity
10mg
Bacteriostatic Water
2ml
Desired Dose
2.5 mg
Use the dose on your prescription. Presets are shortcuts, not recommendations.
How It Works
1. Calculate concentration:
Peptide amount ÷ Water volume = 5.00 mg/ml
Peptide amount ÷ Water volume = 5.00 mg/ml
2. Find required volume:
Target dose ÷ Concentration = 0.500 ml
Target dose ÷ Concentration = 0.500 ml
3. Convert to syringe units:
(Required volume ÷ Syringe volume) × Syringe units = 50.0 units
(Required volume ÷ Syringe volume) × Syringe units = 50.0 units
How to Use the Tirzepatide Calculator
This peptide calculator for tirzepatide turns the milligram dose on your prescription into the number of units to draw on a U-100 insulin syringe. It only does the math. Your prescriber decides the dose, and your pharmacy label tells you the vial size and how much diluent went in.
Step 1: Pick your syringe. Choose the size you actually have: 0.3 mL (30 units), 0.5 mL (50 units), or 1 mL (100 units). If the result is bigger than your syringe holds, the calculator will flag it.
Step 2: Enter your vial size. Use the milligrams printed on the vial label, such as 10 mg. Tap Custom if yours isn't listed.
Step 3: Enter the diluent volume. This is the bacteriostatic water (or other diluent) that was added to the powder. If your pharmacy sent the vial already mixed, use the concentration on the label instead: a vial labelled 5 mg/mL is the same as 10 mg in 2 mL.
Step 4: Enter your prescribed dose in mg. The presets are shortcuts for common numbers, not recommendations. Always use the dose your prescriber gave you.
The result shows the units to draw, the concentration in mg/mL, and the volume in mL. Write the concentration on your vial so you never have to guess next week.
Tirzepatide Units to mg Conversion Table
Units on an insulin syringe measure volume, not drug. On a U-100 syringe, 100 units is always 1 mL. How much tirzepatide sits in those units depends on your vial's concentration, so this table shows the same syringe readings at three common concentrations.
| Syringe units | Volume | At 2.5 mg/mL | At 5 mg/mL | At 10 mg/mL |
|---|---|---|---|---|
| 5 units | 0.05 mL | 0.125 mg | 0.25 mg | 0.5 mg |
| 10 units | 0.1 mL | 0.25 mg | 0.5 mg | 1 mg |
| 20 units | 0.2 mL | 0.5 mg | 1 mg | 2 mg |
| 25 units | 0.25 mL | 0.625 mg | 1.25 mg | 2.5 mg |
| 30 units | 0.3 mL | 0.75 mg | 1.5 mg | 3 mg |
| 50 units | 0.5 mL | 1.25 mg | 2.5 mg | 5 mg |
| 100 units | 1 mL | 2.5 mg | 5 mg | 10 mg |
When You Don't Need This Calculator
Mounjaro and Zepbound, the FDA-approved tirzepatide products, come as ready-to-use pens and vials, per the Zepbound label. Follow the instructions that came with them. This calculator is for compounded tirzepatide in a vial, which is not FDA-approved and isn't reviewed by the FDA for safety or quality. Get it only through a licensed prescriber and pharmacy, never from sellers marketing "research use only" products.
For the mixing process itself, including a full vial-by-vial chart and storage tips, see our guide on how to reconstitute tirzepatide. If you use several peptides, the general peptide calculator works for any of them.
Once you know your number, PeptideKit can remember it for you. It schedules your weekly injection, reminds you when it's due, and keeps a log of every dose and side effect to share with your prescriber.
Frequently Asked Questions
How do I calculate tirzepatide units?
Divide your dose in mg by your vial's concentration in mg/mL to get the volume in mL, then multiply by 100 for units on a U-100 syringe. The concentration is the vial's mg divided by the mL of diluent added. The calculator above does all three steps for you.
How many units is 1 mg of tirzepatide?
It depends on the concentration. At 5 mg/mL, 1 mg is 20 units. At 10 mg/mL, 1 mg is 10 units. Check the concentration on your vial label before converting.
How much tirzepatide is in 10 units?
10 units on a U-100 syringe is always 0.1 mL. At 5 mg/mL that's 0.5 mg of tirzepatide, and at 10 mg/mL it's 1 mg. The conversion table above covers other readings.
Can I use this calculator for Mounjaro or Zepbound pens?
No. Branded pens deliver a fixed dose and don't use syringe units. This calculator is for tirzepatide drawn from a vial with an insulin syringe.
What if the result is more units than my syringe holds?
Don't try to eyeball it. Ask your pharmacy whether you should use a larger syringe. Never change the dose or the diluent volume without your prescriber or pharmacist.
Always consult with qualified healthcare professionals before starting any peptide therapy protocol. This information is for educational purposes only and does not constitute medical advice.