Fussing, back-arching, difficulty settling and short naps are non-specific and can have many causes. Recent timing and tired cues may help you plan a calm wind-down, but no wake-window forecast can determine the cause; seek clinical advice when symptoms are persistent or concerning.
Glossary
Overtiredness
“Overtired” is an informal description caregivers use when a baby seems very tired and difficult to settle; it is not a diagnosis or a precise time threshold.
Related guides
Wake windows: how long awake between sleeps
A wake window is simply the awake time between sleeps, and it grows slowly as your baby does.
Building a calming bedtime routine
A short, predictable wind-down each evening gently signals to your baby that sleep is coming, and consistency is what makes it work.
Try the tool: Wake Window Calculator
Related terms
General information, not medical advice. For concerns about your child, talk with your doctor or child-health nurse.