Missed dose and day-change helper
Enter when the dose was scheduled and when you can take it. The helper applies the rule from the Zepbound and Mounjaro labels: take a missed dose within 4 days (96 hours), otherwise skip it and keep the regular day. A second mode checks a planned change of injection day against the label's 72-hour minimum spacing.
Inputs
Your usual injection day and roughly the usual time.
Pre-filled with the current time on this device. Change it to test a later moment.
What the label says
Enter the scheduled time. The Zepbound and Mounjaro labels use one rule: take the missed dose if it is within 4 days (96 hours); if more than 4 days have passed, skip it and take the next dose on the regular day.
Formulashown in full, nothing hidden
hours late = now - scheduled time take now = 0 <= hours late <= 96 skip = hours late > 96 next regular = scheduled time + 7 days (unchanged) day change ok = (new dose time - last dose time) >= 72 hours
Example: scheduled Monday 9:00, remembered Thursday 20:00. That is 83 hours late, inside 96, so the label says take it and keep next Monday. Remembered Friday 10:00 is 97 hours, so skip and take Monday's dose as normal.
Assumptions, checked September 4, 2026
- Zepbound section 2.3 and Mounjaro section 2.1: administer a missed dose as soon as possible within 4 days (96 hours); if more than 4 days have passed, skip it and take the next dose on the regularly scheduled day, then resume the weekly schedule.
- Same sections: the day of weekly administration can be changed if the time between the two doses is at least 3 days (72 hours).
- Times are compared on this device's clock and time zone. Cross a time zone and the hour count can be off by the zone difference; the day count will still be right.
- The tool never suggests doubling a dose, changing a dose, or catching up on more than one missed dose.
- Compounded tirzepatide carries no FDA label. These are the brand rules; your prescriber's written instructions govern.
This calculator is an arithmetic aid for medication a licensed prescriber has already prescribed. It does not recommend a dose. Confirm any result with your prescriber or pharmacist before use.
Read before you use it
Guides for this calculator
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Educational, not medical advice. Read the medical disclaimer.