Frequently Asked Questions

No. This is a reference checklist compiled from the CDC "Learn the Signs. Act Early." and Korean Pediatric Society guidelines. Actual developmental assessment must be performed by a pediatrician or developmental specialist.

Usually not. Some babies lead with motor skills, others with language. Being advanced in one domain does not imply the others, and a lag in one domain with typical progress in others is often not a concern on its own.

Completed months from birth. For babies born more than 6 weeks early, use corrected age (counted from the due date) until about 24 months to avoid underestimating development.

Yes — first steps anywhere between 9 and 18 months is within normal range. As long as other gross-motor milestones (pulling to stand, cruising) are present, this is usually fine. If your child is not standing or walking by 18 months, consult your pediatrician.

Expressive vocabulary varies widely, but if an 18-month-old has no meaningful words, poor eye contact, or does not follow simple gestures (look where you point, "come here"), a pediatric and speech evaluation is recommended. Toddlers with normal receptive language but delayed expression ("late talkers") often catch up by 24 months.

Understanding that an object still exists when it is out of sight. It typically develops between 8 and 12 months and can be observed when a baby looks for a toy hidden under a blanket — it's also why babies love peekaboo around this age.

Only in your browser's local storage. Nothing is sent to a server, so records persist on the same device and browser. This is by design (no signup required). Clearing browser data will also clear your checks.

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Nothing special. It is common for one or two domains to run a little ahead of average, and this does not imply the other domains will too. Keep offering warm, engaged stimulation.

"Monitor" does not mean "problem". It means the milestone is past its typical upper bound and worth mentioning at your next check-up. A cluster (2+ in one domain, or flags across several domains) is worth a more proactive evaluation.

Korea: free infant/toddler health check-ups at public health centers, pediatric rehabilitation clinics, and developmental-rehabilitation service vouchers. US: free evaluations through state Early Intervention programs (under 3) or your local school district (3+).

AAP recommends no screens other than video chats before 18 months. If you introduce screens at 18-24 months, co-view short, high-quality content. During peak language windows, real faces, speech, and books are far more effective than screens.

Loose reference is fine, but variation within the same family is common. Use the CDC / pediatric-society ranges as your anchor rather than sibling comparisons — it is usually less stressful.

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Based on the CDC "Learn the Signs. Act Early." 2022 revision, the Korean Pediatric Society developmental guidelines, and AAP Bright Futures. Last reviewed: 2026-04-19.