Split dose calculator
Free calculator, no sign-up
Divide a weekly dose into smaller, more frequent injections.
Enter your numbers
Arithmetic on the numbers you enter. Check the result against your pharmacy label and ask your prescriber. Reko does not suggest doses, and this is not medical advice.
How it works
The weekly dose divided by the number of injections. The schedule itself is a decision for you and your prescriber.
- Each injection = weekly dose ÷ N.
- Gap in days = 7 ÷ N. When that is not a whole number, alternate: for N = 2, a gap of 3 days then 4 days.
Check it against your label
- The minimum interval between doses in your label. Mounjaro and Zepbound say at least 3 days (72 hours). Ozempic says at least 2 days (more than 48 hours). Those rules are written for moving the day of a once-weekly dose. They do not describe splitting one, and Wegovy gives no such minimum, only a missed-dose rule. Ask your prescriber before splitting.
- Whether your prescriber agrees to splitting at all.
- Whether the smaller amount can be measured with your device or syringe.
Frequently asked questions
In short
- Each injection = weekly dose ÷ number of injections.
- Spacing = 7 days ÷ number of injections, rounded to whole days.
- The total over the week stays the same only if the spacing is kept.
- The label may state a minimum time between doses. Check it.
Does splitting change the total?
Not if you keep to the same total and calendar.
Why alternate gaps?
Seven does not divide evenly by two.
Can I split on a pen?
Pens have fixed steps. See the click pages for what that involves.
What does this tool do?
Some people divide a weekly dose into two or more smaller injections. This tool does the division. It does not say whether splitting is appropriate.
A worked example
Example. These numbers are made up to show the steps. They are not a label value and not a suggestion.
Made-up: a weekly 4 mg split in 2. Each injection is 2 mg. Gaps alternate 3 and 4 days, for instance Monday and Thursday.
Split in 7 for daily: 4 ÷ 7 is about 0.57 mg, which may be hard to measure.
Related pages
How Reko does this in the app
In Reko you can build a schedule that is weekly, daily or in other patterns, and each injection has its own entry with the amount and time. By default, reminders leave out the medication's name.
Reko records what you and your prescriber decide. It never suggests a dose, and this page is not medical advice.