Developmental leap calculator

Around each leap your baby's brain takes a big developmental step and the world suddenly looks different. That's why fussy phases — more crying, clinginess and crankiness — often show up right before a new skill does.

Leaps follow gestational age, so they're counted from the due date — not the birthday.

1. Leap 1New sensationsWeeks 4–6

   The world suddenly feels more intense. Expect extra crying and cuddling, then a more alert baby and the first real smiles.

2. Leap 2PatternsWeeks 7–9

   Your baby starts spotting simple patterns: staring at their own hands, lights and shadows, and listening closely to sounds.

3. Leap 3Smooth transitionsWeeks 11–13

   Movements and sounds get smoother — fluid eye tracking, squealing, gurgling and much more purposeful reaching.

4. Leap 4EventsWeeks 14–19

   Short sequences start to make sense: your baby shakes, bangs, grabs and mouths everything within reach.

5. Leap 5Distance & relationshipsWeeks 22–26

   Baby now understands distance — including that you can walk away. Separation anxiety often starts around this leap.

6. Leap 6CategoriesWeeks 33–37

   Everything gets examined and compared as your baby starts sorting the world into groups — a dog is not a cat!

7. Leap 7SequencesWeeks 41–46

   Steps get chained together: stacking blocks, fitting shapes, pointing at things to hear their names.

8. Leap 8ProgramsWeeks 50–55

   Everyday routines click into place — your toddler “helps” with dressing, cooking and cleaning, and imitates everything.

9. Leap 9PrinciplesWeeks 59–64

   Meet your little planner: strategies appear, rules and boundaries get tested, and the first tantrums may arrive.

10. Leap 10SystemsWeeks 70–76

    The big picture forms — me and you, mine and yours — along with the first signs of empathy and conscience.

Every baby is different — leap timing is a guide, not a schedule. If anything about your baby's development worries you, talk to your pediatrician.