MoonleapGet MoonleapBaby leap calculator
Enter your baby's due date to see when each of the 10 developmental leaps is likely to start, peak and pass.
All 10 leaps by week
Weeks are counted from the due date. Every baby has their own timing, so treat these as typical windows, not deadlines.
| # | Leap | Window | Peak | What's changing |
|---|---|---|---|---|
| 1 | Brighter World | weeks 4.5–5.5 | week 5 | Senses wake up and the world gets louder and brighter |
| 2 | Noticing Shapes | weeks 7.5–9.5 | week 8.5 | Spotting the simple repeats that make up the world |
| 3 | Flowing Movement | weeks 11.5–12.5 | week 12 | From jerky starts to smooth, gliding changes |
| 4 | Cause & Effect | weeks 14.5–19.5 | week 17 | One thing leads to another, and baby wants to try it all |
| 5 | Near & Far | weeks 22.5–26.5 | week 25 | Discovering space, distance and where things go |
| 6 | Sorting the World | weeks 33.5–37.5 | week 35.5 | Noticing what belongs together and what doesn't |
| 7 | Step by Step | weeks 41.5–46.5 | week 44 | Learning that one thing leads to the next |
| 8 | Making Plans | weeks 50.5–54.5 | week 52.5 | Finding more than one way to get there |
| 9 | Choices & Rules | weeks 59.5–64.5 | week 62 | Testing the rules and finding clever ways around them |
| 10 | Who I Am | weeks 70.5–76.5 | week 73.5 | Growing a sense of self, family and what matters |
Questions
How are baby leap dates calculated?
Leaps are counted from your baby's due date, not the birth date, so a baby born early or late follows the same developmental clock. Each leap has a typical start, peak and end week after the due date.
How many leaps are there?
Moonleap follows 10 leaps from the due date to about 18 months, from "Brighter World" around week 5 to "Who I Am" around week 73.5.
What are the signs of a leap?
Many babies cry more, want to be held more, sleep less well and have quick mood changes for a few days, and then show new skills. Every baby has their own timing; these are common signs, not a checklist.
Is a leap the same as a sleep regression?
They often overlap. A fussy stretch with worse sleep around the same age is what many parents call a regression; looking at it as a developmental leap explains why it passes and what new skill follows.