Tirzepatide Dosage Calculator — mg, mL & U-100 Units
Tirzepatide (marketed as Mounjaro for diabetes and Zepbound for weight loss) is a powerful GLP-1 and GIP receptor agonist that requires careful dose titration. Our free tirzepatide dosage calculator helps you determine the correct number of units for your current dose, accounting for different vial concentrations. Whether you're starting your journey or adjusting your maintenance dose, this tool simplifies the math so you can focus on your health goals.
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.
Peptide Dossier Editorial Team · Calculation and titration corrections: September 8, 2026. Arithmetic verification is separate from clinical review.
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 a four-week starting period, then response- and tolerability-based escalation. Further increases require at least four weeks at the current dose. A calendar does not mean everyone must reach the maximum.
The calculator deliberately does not select an amount from the week number. Use your actual instructions, including the exact product and indication. References checked September 8, 2026.
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 dose can require different unit measurements depending on your vial concentration. Always check your medication label before calculating to ensure accuracy.
Common Vial Concentrations
These three concentrations are arithmetic examples, not an exhaustive product list or a universal branded standard. Use the actual concentration on the supplied product.
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 example does not identify the concentration or delivery device of every Mounjaro or Zepbound presentation.
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
As you progress through the tirzepatide titration schedule, side effects are common but typically manageable with proper strategies.
- 1.
Time Your Injections Wisely
Inject on a consistent day each week. Many patients find injecting before bed helps them sleep through initial nausea. Avoid injecting before important meals or social events.
- 2.
Adjust Your Diet Gradually
Reduce portion sizes and avoid fatty, greasy foods. Stick to bland, easy-to-digest meals for 2–3 days after dose increases. Small, frequent meals are often better tolerated than large ones.
- 3.
Stay Hydrated
Drink plenty of water and sugar-free beverages. Dehydration can worsen nausea. Aim for at least 8–10 glasses of water daily, especially after dose increases.
- 4.
Discuss Medications with Your Doctor
If nausea is severe, ask your doctor about antiemetic medications like ondansetron or metoclopramide. They may also recommend slowing your titration schedule if side effects are intolerable.
- 5.
Monitor Your Energy
Side effects typically subside within 3–5 days of injection. If fatigue persists beyond this window, report it to your doctor. Keep a symptom journal to track patterns.
Frequently Asked Questions
The standard starting dose for tirzepatide is 2.5 mg injected subcutaneously once weekly. This low dose helps your body adjust to the medication and minimizes initial side effects.
Zepbound starts at 2.5 mg weekly for four weeks, then 5 mg weekly. Further increases are in 2.5 mg steps after at least four weeks at the current dose, considering response and tolerability—not every week.
Yes! This calculator works with all common vial concentrations: 5 mg/mL, 10 mg/mL, and 20 mg/mL. Enter your vial concentration to get accurate unit measurements for your dose.
The maximum maintenance dose is typically 15 mg once weekly. Some patients may not need this highest dose; your doctor will determine the optimal dose for your weight loss or diabetes management goals.
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.
The standard schedule applies to most patients, but your doctor may adjust it based on your tolerance, side effects, or medical history. Never change your dosing schedule without medical guidance.
Related Guides & Resources
Medical Disclaimer
This dosage calculator is for educational purposes only and does not replace medical advice from your healthcare provider. Always follow your doctor's prescribed dosing schedule. If you experience severe side effects or have questions about your tirzepatide regimen, contact your physician immediately. Do not adjust your dose without explicit medical guidance.