How many clicks, how much volume and how many units on an insulin syringe a given dose of Mounjaro (tirzepatide) works out at from a given KwikPen strength — with the arithmetic shown, so you can check it rather than trust it.
This is a calculator, not advice. It converts between milligrams, millilitres and clicks. It does not suggest what dose you should be on, and nothing on this page is a recommendation to change one. Dose changes belong with you and your prescriber.
The licensed way to use a multiple-dose pen is four doses of 0.6 mL. Dialling a part-dose, or drawing solution out of a device with a syringe, is outside the product information. Dose accuracy is only guaranteed for the doses the device is designed to deliver, and it is not guaranteed at the end of a cartridge.
No medicines are sold, supplied, promoted or advertised on this site. Figures here describe what is in a device; they say nothing about whether you should use it that way.
1 · Pen or device
2 · Pen strength
3 · Pen style
4 · Target dose (mg)
5 · Leftover volume
6 · Price paid for the pen (optional)
Estimated clicks & volume
Dose
Doses per pen
Cost per dose (one week)
One constant does all of it: 1 click = 0.01 mL. A multiple-dose pen’s labelled
dose is 0.6 mL, which is 60 clicks, and the strength printed on the pen
is the milligrams in that 0.6 mL. So:
clicks = target mg ÷ pen mg × 60 and
mL = clicks ÷ 100
A 5 mg dose from a 12.5 mg pen is 5 ÷ 12.5 × 60 = 24 clicks, which is
0.24 mL. The cartridge holds 12.5 mg in 0.6 mL, so 20.83 mg per mL, and
0.24 × 20.83 = 5.0 mg. The two directions agree, which is the point of showing both.
0.01 mL is also one unit on a U-100 insulin syringe, which is why the same number serves a vial drawn up with a syringe as serves a pen counted by ear. Only the word changes.
The pen styles. Both styles deliver the same four 0.6 mL doses. What differs is how much solution is left when the counter stops — the older cartridges hold about 3.2 mL and the newer ones about 2.6 mL, against 2.4 mL of labelled doses. Those totals are community measurement, not manufacturer specification, and they are used here only for the leftover-volume figure. Expiry dating is a rough guide to which is which, not a rule.
Pen photographs are of the Mounjaro KwikPen and are shown to identify which device the arithmetic applies to — the click model is only correct for a particular pen, and a reader who cannot tell which one is in their fridge cannot use the answer. Mounjaro and KwikPen are trade marks of Eli Lilly and Company, who are not connected with this site and have not endorsed it.
Mounjaro (tirzepatide) is a prescription-only medicine. This page exists because people already do this arithmetic, usually on the back of an envelope, and an arithmetic error is worse than an arithmetic tool. It is not a recommendation to split doses, to extract extra volume, or to use any device other than as its product information describes. If a number here disagrees with your prescriber or your pharmacist, they are right and this page is wrong.