The Today screen ends on a line about what is likely next, and a reminder arrives when something looks overdue. This page is what sits behind both. You do not need any of it to use moppet.
Before moppet knows anything about your child, it uses the feeding and sleep cadence published for their age. Which body it follows depends on where the child is, taken from the time zone on their profile:
That changes the numbers, because the guidance itself differs. The AAP describes a breastfed newborn nursing about every two hours, measured from the start of one feed to the start of the next, which is ten to twelve sessions a day. The NHS and the WHO describe responsive feeding, which in practice runs a little more often early on. So a newborn's starting cadence is a little under two hours under the AAP, and slightly shorter again under the NHS and WHO. The two converge as the child gets older, and both land near three and a half hours by six months.
It is keyed to the child, not to you. A grandparent in London and a parent in New York see the same “Next” for the same child. A shared record that told the two of them different things would be worse than no record at all.
Diaper and sleep cadences are not split by country. No health body specifies a materially different diaper cadence, and sleep works the same way everywhere, so those starting figures are the same wherever you are.
A feed at 2am is not a feed at 2pm. So moppet keeps the two apart. The overnight gap is longer, and it lengthens faster as your child grows. Your child's own day and night patterns are learned separately too, so a good run of nights does not stretch out your afternoon.
A nap is not counted from the last nap. It is counted from the moment your child last woke up, plus the length of time a child that age can comfortably stay awake. That stretch is the wake window, and it widens as they grow: under an hour for a newborn, several hours by the time they are two. It moves gradually, so the window grows by a few minutes a week and never jumps on a birthday.
The ranges come from pediatric sleep practice, and the total-sleep figures behind them are the American Academy of Sleep Medicine consensus, which the AAP endorses. While a sleep timer is running there is no nap prediction, because your child is already asleep. Today says so instead. If a timer has been running longer than any real sleep, moppet stops treating it as sleep and predicts again, so a timer nobody stopped cannot switch your nap reminders off.
The published cadence is only the starting point. moppet looks at the last few weeks of your own logs, takes the typical gap for the time of day, and blends it with the published figure. Early on the published figure dominates, because it is all there is. Within a few days of ordinary logging your child's own rhythm carries most of the weight.
It uses the typical gap and not the average, so one four-hour Sunday afternoon does not drag the whole estimate out.
A feed that happens but never gets logged does not leave a hole in the record. It makes two gaps look like one long one. The error only runs one way: missing logs make your child look slower than they are, never faster. Left alone, an app would read a patchy day as a placid baby and push the next feed hours out.
So moppet weighs its own evidence. A gap far longer than the published cadence for that age is more likely to be a missed log than a real one, and counts for less. The less of the day moppet can see, the more it leans on published guidance, and the window cannot run away from it. If you log normally, none of this changes anything you see. It is a correction for missing information.
Underneath everything there is a floor: the earliest moment moppet is willing to nudge. The prediction can move a reminder later than the floor when your child genuinely runs longer, and it never pulls one earlier. If you set your own reminder threshold, your number wins in both directions.
moppet also stops when a reminder would stop being useful:
The prediction runs on your own logged data, on our servers. Nothing is sent to an outside service to work it out. Notifications are the exception, and there are three of them. To reach your phone a reminder passes through Expo and then whichever notification service your phone uses, Apple or Google, all of it in the United States, carrying your child's first name, and for a medication reminder the medicine and the dose. The alert when another caregiver stops a timer takes that same path, carrying that caregiver's name and the span the timer covered. Another caregiver's running timer appearing on your lock screen carries the kind of timer and the time it started, with no name of any kind. On an iPhone it takes a shorter route, to Apple alone rather than through Expo; on an Android phone it goes through Expo and then Google, the same way a reminder does. That one stays off until you switch it on.
Treat the result as a likely window. It is a nudge about your record rather than an instruction about your child.