Tirzepatide Dosage Calculator — mg, mL & U-100 Units
This tirzepatide calculator converts an entered amount and the actual labeled liquid concentration into mL and U-100 units. Use the amount on your prescription and the concentration on your supplied product. The tool performs arithmetic; it does not choose a treatment dose or operate a pen.
How to Use This Calculator
Select tirzepatide and enter the amount per administration in mg and the actual labeled concentration in mg/mL. The result is liquid volume, not a prescription, pen-click conversion, or guarantee of measurement precision. Optional vial volume enables quantity and cost estimates.
This tool converts an amount you enter into liquid volume. It does not select a dose or titration schedule. Use the instructions and concentration for your actual product; it does not convert pen clicks, tablets, or powder-mixing instructions.
Select Medication
Your product and entered amount
Enter mg per administration and the labeled mg/mL, not the total mg in the container. Full-vial solution volume is optional and means liquid volume, not container capacity.
Volume calculation
Enter an amount and labeled concentration to calculate volume.
Week tracking
Recordkeeping only: changing the week or date never changes your entered amount. A future start date displays week 1.
Current Week 1
Full-Vial Supply Estimate
Enter valid amount, concentration, and full-vial solution volume to estimate supply. Values must be within the calculator’s numerical range.
Assumes a full vial now, one administration per week, no dose changes and no handling losses. Counts complete portions only. Not a refill date, shelf-life estimate, or authorization to keep a vial in use.
Titration: product-specific references
A calendar week alone does not determine a dose. Product, indication, response and tolerability matter. Ozempic and Wegovy do not share one interchangeable dosing schedule; a branded product’s label also does not establish the instructions for a compounded vial.
Retatrutide is not Mounjaro. Mounjaro contains tirzepatide; Lilly describes retatrutide as investigational. The retatrutide option provides arithmetic, not a recommended treatment schedule. References checked September 8, 2026.
Tirzepatide Titration Schedule Explained
The Zepbound prescribing information, sections 2.1–2.2, describes 2.5 mg once weekly for four weeks, followed by 5 mg once weekly; later 2.5 mg increases require at least four weeks at the current dose and depend on response and tolerability. The Mounjaro prescribing information, sections 2.1–2.2, permits further 2.5 mg increases after at least four weeks when additional glycemic control is needed.
Zepbound maintenance is 5, 10, or 15 mg weekly for adult weight management and 10 or 15 mg for obstructive sleep apnea. Mounjaro's maximum is 15 mg weekly in adults and 10 mg in pediatric patients aged 10 years and older. The calculator does not select an amount from the week number.
How to Calculate Tirzepatide Units
Converting tirzepatide from milligrams to units is straightforward once you know your vial concentration. The formula is simple:
U-100 units = Amount (mg) ÷ Concentration (mg/mL) × 100
Example Calculations
- 5 mg dose with 10 mg/mL vial: 5 ÷ 10 × 100 = 50 U-100 units (0.5 mL)
- 7.5 mg dose with 20 mg/mL vial: 7.5 ÷ 20 × 100 = 37.5 U-100 units (0.375 mL)
- 10 mg dose with 5 mg/mL vial: 10 ÷ 5 × 100 = 200 U-100 units (2 mL; exceeds a 1 mL syringe, not an administration recommendation)
The same amount can require different unit measurements depending on the labeled concentration. Check the supplied product label before calculating; the arithmetic does not verify the prescription, formulation, or device.
Common Vial Concentrations
These three concentrations are arithmetic examples, not an exhaustive product list or a universal branded standard. Use the actual positive concentration on the supplied product; total vial mg and mg/mL are different fields.
5 mg/mL Concentration
At 5 mg/mL, a hypothetical 10 mL solution contains 50 mg. For the same mg amount, a lower concentration requires a larger—not smaller—liquid volume.
10 mg/mL Concentration
At 10 mg/mL, a hypothetical 3 mL solution contains 30 mg. This calculation says nothing about the concentration or delivery device supplied with a specific product.
20 mg/mL Concentration
At 20 mg/mL, 0.01 mL contains 0.2 mg. A more concentrated solution requires less volume for a given mg amount; that does not make it preferable or easier to measure.
Tips for Managing Side Effects During Dose Increases
In Zepbound studies, nausea, vomiting, and diarrhea often occurred during dose increases and generally decreased over time, according to Lilly's patient guidance. That does not establish a fixed recovery day for an individual.
- 1.
Time Your Injections Wisely
Choose a consistent weekly day. Zepbound can be taken any time of day, with or without meals; bedtime is not required.
- 2.
Adjust Your Diet Gradually
Lilly suggests smaller meals, stopping when full, avoiding fatty foods, and trying bland foods such as toast or rice when nauseated. Adjust to what you tolerate rather than following a fixed two- or three-day diet.
- 3.
Stay Hydrated
Drink fluids to reduce dehydration risk, following any personal fluid restrictions. Persistent vomiting or diarrhea, or difficulty keeping fluids down, needs prompt medical advice.
- 4.
Discuss Medications with Your Doctor
Have your prescriber assess troublesome symptoms before adding an anti-nausea medicine or increasing the dose. Mounjaro's patient guidance calls for medical attention when stomach problems are severe or persist.
- 5.
Monitor Your Energy
Record fatigue, food intake, and symptom timing to discuss at follow-up. Do not wait for a presumed recovery day if symptoms are serious: persistent or severe abdominal pain can indicate pancreatitis; stop the medication and seek urgent assessment.
Frequently Asked Questions
Zepbound and Mounjaro start at 2.5 mg subcutaneously once weekly. Zepbound uses this for four weeks, not maintenance. What follows depends on the product and treatment plan; this calculator does not choose a starting dose.
Zepbound uses 2.5 mg increases after at least four weeks at the current dose, based on response and tolerability. Mounjaro permits further 2.5 mg increases after at least four weeks when additional glycemic control is needed. This is not an every-week or automatic calendar change.
Yes, when the entered amount and actual labeled mg/mL concentration are positive. The 5, 10, and 20 mg/mL examples are arithmetic examples, not an exhaustive or branded-standard list. The calculator cannot select a dose or validate a product.
Zepbound maintenance is 5, 10, or 15 mg weekly for adult weight management, but 10 or 15 mg for obstructive sleep apnea. Mounjaro's maximum is 15 mg weekly in adults and 10 mg in pediatric patients aged 10 years and older.
Divide the entered mg by the labeled mg/mL to get mL, then multiply by 100 for U-100 units. Example: 7.5 mg ÷ 20 mg/mL = 0.375 mL = 37.5 U-100 units. This is arithmetic, not a dose recommendation.
No. Product, indication, age, response, tolerability, and prescriber instructions can change the plan; titration is not a universal calendar. Do not change it without medical guidance.
Related Guides & Resources
Medical Disclaimer
This calculator explains volume arithmetic, not treatment selection. Follow your prescribed dose and the instructions for your exact product and device. An accurate calculation does not establish that a dose is appropriate or that a volume can be measured with your syringe.