Wonder Weeks Calculator

Find out if your baby is going through a developmental leap. Based on the 10 major mental leaps in the first 20 months.

All 10 Developmental Leaps

Leap 1: Changing Sensations

Awareness of sensory input changes

Week 4.5–5.5

Leap 2: Patterns

Recognizing simple patterns

Week 7.5–8.5

Leap 3: Smooth Transitions

Perceiving smooth transitions in movement and sound

Week 11.5–12.5

Leap 4: Events

Understanding short sequences of events

Week 14.5–19.5

Leap 5: Relationships

Understanding spatial relationships

Week 22.5–26.5

Leap 6: Categories

Categorizing and grouping

Week 33.5–37.5

Leap 7: Sequences

Understanding and performing sequences

Week 41.5–46.5

Leap 8: Programs

Applying programs — flexible problem solving

Week 50.5–54.5

Leap 9: Principles

Understanding principles and values

Week 59.5–64.5

Leap 10: Systems

Understanding systems and adapting to them

Week 71.5–75.5

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