Measurement guide
Consistent technique matters more than any single number.
Height: lying vs. standing
Younger children are usually measured lying down, and older children standing up. The transition age varies by clinic and guideline, so this site does not state one exact cutoff month. What matters is recording which method was used, since lying-down length and standing height are not perfectly interchangeable.
Weight & head circumference
Weigh with minimal clothing when possible, and note whether a diaper was on. For head circumference, wrap the tape around the widest part of the head (above the eyebrows and ears) and record the largest reading from a few attempts.
BMI applies from 24 months
Official BMI reference values are only available starting at 24 months (2 years old). Before that, height and weight trends are used instead.
Why the same tool and time matter
Using the same scale, the same tape measure, and roughly the same time of day makes repeated measurements more comparable. A single measurement can shift with clothing, feeding, or mood — the trend across several visits matters more than any one number.
Home vs. clinic measurements
Home and clinic measurements can differ because of tool calibration and posture. This site does not automatically flag a difference between the two as abnormal — it simply suggests noting the difference and, if you're concerned about a growth trend, checking with a professional.
Quick checklist
- Use the same tool each time, if possible.
- Note the time of day and whether a diaper/clothing was on.
- Record whether height was measured lying down or standing.
- Take a couple of readings and use the more consistent one.
- If a reading looks unusual, re-measure rather than assuming it's wrong.
Sources
2017 Korean Children and Adolescents Growth Chart (KDCA · Korean Pediatric Society · NHIS LMS data); general measurement guidance informed by WHO Child Growth Standards (no specific unverified cutoff numbers were reused from WHO material).
작성일 2026-08-07 · 검토일 2026-08-07