What is the tirzepatide dose calculator?

It is the same GLP-1 unit-conversion math, pre-set to tirzepatide-typical inputs. It returns the U-100 syringe units and milliliter draw for a chosen weekly dose at a chosen vial concentration.

Which tirzepatide products does the FDA reference for dose steps?

Mounjaro (FDA-approved for type 2 diabetes) and Zepbound (FDA-approved for chronic weight management and obstructive sleep apnea with obesity in adults) both reference 2.5, 5, 7.5, 10, 12.5, and 15 mg weekly steps in their labels.

Does this calculator know my real concentration?

No. It returns math against the concentration you type. Research vials reconstituted by the user can land at different concentrations depending on how much bacteriostatic water was added.

Is the tirzepatide research-vial workflow FDA-approved?

No. Branded Mounjaro and Zepbound pens are FDA-approved. Compounded tirzepatide is not FDA-approved. The calculator is educational and does not endorse any particular sourcing path.

What does the tirzepatide dosage chart show?

It lists the FDA-approved Mounjaro and Zepbound weekly dose steps: a 2.5 mg starting dose for the first 4 weeks (an initiation step, not a maintenance dose), then 2.5 mg increases no sooner than every 4 weeks, up to a maximum of 15 mg weekly.

How do I convert a tirzepatide dose in mg to syringe units?

Divide the weekly dose in mg by the vial concentration in mg/ml to get the draw volume in ml, then multiply by 100 to read U-100 insulin syringe units. For example, 5 mg from a 10 mg/ml vial is 0.5 ml, which is 50 units. The converter on this page works in both directions.

How much bacteriostatic water do I add to a tirzepatide vial?

Concentration in mg/ml equals the vial mass in mg divided by the bacteriostatic water volume in ml. For example, a 10 mg vial in 1 ml of BAC water is 10 mg/ml. The reconstitution calculator on this page returns the concentration so you can carry it into the dose converter.

What happens if I miss a weekly tirzepatide dose?

The Mounjaro and Zepbound labels say a missed weekly dose can be taken within 4 days (96 hours). After that, skip it and take the next dose on the regular day. To change the dosing day, the label asks for at least 3 days (72 hours) between doses. Doubling up to catch up is not part of the labeled rule.

How fast can the tirzepatide dose be increased?

Per the FDA label, the dose increases in 2.5 mg steps no sooner than every 4 weeks. Increasing faster than the label is associated with more nausea and vomiting. This calculator is educational and does not set a schedule for you.

Does this calculator predict my weight loss?

No. The weight-loss timeline is plain date math on a weekly rate you enter. The reference table on this page shows average results reported in the SURMOUNT clinical trials, with citations. Those are population averages, not a prediction for any one person.

Is the printable dosing table an official document?

No. The print view is an educational snapshot of the dosage chart and your calculated numbers. It is not a prescription, a pharmacy label, or medical advice. Follow your own product label and prescriber.

How many units is 7.5 mg of tirzepatide?

It depends on the vial concentration, because units measure volume, not milligrams. At 10 mg/ml, 7.5 mg is 0.75 ml, which is 75 units on a U-100 insulin syringe. At 20 mg/ml the same 7.5 mg is 0.375 ml, or about 38 units. Enter your own concentration in the converter, or read the dose-to-units table on this page.

What if my vial label says a mass per 0.5 ml?

Convert it to milligrams per milliliter first. A label that reads 5 mg per 0.5 ml is 10 mg/ml, because you double the mass to cover a full milliliter. Enter that mg/ml value in the calculator. Labels are written several ways, so always reduce them to mg/ml before drawing.

Can different pharmacies use different tirzepatide concentrations?

Yes. The FDA has noted that compounded GLP-1 strengths vary between pharmacies, and one pharmacy can make several strengths. That is why drawing a familiar volume without recalculating for the specific vial is a documented cause of overdose. Recalculate units for each vial using its own concentration.

Why do the syringe units change when the concentration changes?

The milligram dose stays the same, but a higher concentration packs those milligrams into less liquid, so the draw volume and the U-100 unit count both go down. The dose-to-units table on this page shows the same weekly dose across several concentrations so the pattern is easy to see.

Can I use this calculator for a Zepbound or Mounjaro pen?

No. Mounjaro and Zepbound pens are pre-mixed, fixed-dose click devices, so there is no concentration to enter and no volume to draw. This calculator is for vial-level math: drawing a reconstituted vial with an insulin syringe. For a branded pen, follow the pen instructions and your prescriber.

Tirzepatide dose calculator

Quickly convert your tirzepatide vial concentration to U-100 syringe units and milliliters. Free dosage chart, mg-to-units converter, and reconstitution tool.

What this calculator returns

The U-100 insulin syringe unit count for the chosen weekly tirzepatide dose.
The equivalent draw volume in milliliters.
Default presets that mirror the FDA-approved Mounjaro and Zepbound label dose steps (2.5, 5, 7.5, 10, 12.5, 15 mg weekly).
An FDA-label dosage chart for the Mounjaro and Zepbound dose steps.
A bidirectional mg to U-100 units converter.
A vial reconstitution calculator (vial mg plus bacteriostatic water in ml gives mg/ml).
A weight-loss timeline estimate plus a SURMOUNT trial-average reference table with citations.
A common dosing mistakes list and a printable dosing table.
A worked conversion that shows the mg, ml, and U-100 unit math for the dose you enter.
A U-100 syringe draw preview for the calculated dose.
A dose-to-units conversion table across common vial concentrations.

Formula and example

Tirzepatide vial draw math uses the same GLP-1 conversion formula: dose in mg divided by concentration in mg/ml equals ml.

The U-100 unit count is the ml draw multiplied by 100.

Reconstituted concentration in mg/ml equals vial mass in mg divided by bacteriostatic water volume in ml.

The dose-to-units table applies that same formula across several vial concentrations so higher concentrations read as fewer units.

Worked example: A 5 mg weekly dose from a 10 mg/ml tirzepatide vial equals 0.5 ml, or 50 U-100 units.

Warnings and boundaries

Mounjaro and Zepbound pens are FDA-approved branded products with their own instructions.
Compounded tirzepatide is not FDA-approved.
The calculator returns math for the concentration entered, not a sourcing or dosing endorsement.
Weight-loss figures are average results from the SURMOUNT trials, not a personal prediction.

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For research and educational purposes only. Not medical advice.