Complete Guide to Baby Growth Tracking: Weight, Height, and Head Circumference
A growth chart is a child's own measurements plotted against a reference, not a mark they have been given. Growth has been tracked at every well-child visit for decades because it is one of the most reliable indicators of overall health, and consistent growth along a child's own curve matters more than where they fall on the chart. The post's rule is that a baby in the 20th percentile who stays there is typically healthier than a baby who drops from the 80th to the 30th. Three things get measured: weight, length and head circumference. Any centile between the 5th and the 95th is considered normal, on the post's account. Nothing here is a mark.
Why Growth Tracking Matters
Pediatricians have tracked infant growth for decades because it is one of the most reliable indicators of overall health. Consistent growth along a child's own curve matters more than where they fall on the chart. A baby in the 20th percentile who stays there consistently is typically healthier than a baby who drops from the 80th to the 30th percentile.
What Gets Measured
Weight
Measured at every well-child visit. Babies typically:
- Double birth weight by 4-5 months
- Triple birth weight by 12 months
- Gain 5-7 ounces per week in the first months, slowing to 3-5 ounces per week by 6 months
Length/Height
- Newborns average 19-21 inches
- Babies grow about 10 inches in the first year
- Growth is not always steady. Babies often grow in spurts
Head Circumference
This measurement tracks brain growth:
- Average newborn head circumference: 13.5-14 inches
- Head circumference increases about 4 inches in the first year
- Rapid or slow head growth can indicate important health conditions
Understanding Growth Charts
Growth charts show how your baby compares to a large population of same-age, same-sex babies. The WHO growth charts are standard for children under 2.
Percentiles explained:
- 50th percentile means half of babies are larger and half are smaller
- 25th percentile means 25% of babies are smaller, 75% are larger
- Any percentile between 5th and 95th is considered normal
What matters most is that your baby follows their own growth curve consistently. Crossing two or more major percentile lines warrants medical evaluation.
Tracking With LifeWell
The baby tracker's growth feature provides:
- Easy measurement logging with date and value
- Growth charts that plot your baby's data on WHO curves
- WHO percentile bands for weight and length. Head circumference is plotted on its own, because LifeWell does not carry the published head-circumference tables and a band drawn from numbers it does not have would be worse than no band at all
- No alerts. Nothing here tells you a measurement looks worrying. Your health visitor plots this against the real chart, and that is the conversation to have
- Visit history to review all measurements in one place
Tips for Accurate Measurements
- Weigh at the same time of day, preferably before feeding
- Use the same scale for consistency
- Measure length on a flat surface with legs fully extended
- Measure head circumference at the widest point, just above the ears
When to Be Concerned
Talk to your pediatrician about:
- Weight loss after the initial newborn period
- Crossing two or more percentile lines in either direction
- Head circumference growing much faster or slower than weight and length
- Not regaining birth weight by 2 weeks of age
Remember, growth charts are tools for tracking trends, not scorecards. Your baby's overall health, energy, and developmental milestones matter just as much as the numbers on the chart.
Elsewhere on LifeWell
- Privacy — What LifeWell stores, where it sits, and who can read it back.
- Plans — What the free plan includes, and what each paid one adds.
- Export everything — Your whole record leaves in one file, on any plan, without giving a reason.
What people use it for
Add a measurement
Add a measurement at `/baby/growth` with the date, the weight and the length, ticking "Measured lying down" when that is what you did, because lying reads about 0.7 cm longer than standing and the WHO tables account for the switch at two years.
Put the child's sex on the record so the reference bands…
Put the child's sex on the record so the reference bands appear. Without it the line is still yours, and the bands stay off because the WHO publishes separate tables for girls and boys.
Record head circumference knowing it is plotted with no…
Record head circumference knowing it is plotted with no band beside it. Your health visitor holds the real chart.
Take the numbers to the appointment
Take the numbers to the appointment. The growth page exists to be read by the person who examines your child, never instead of them.
Questions
What does a centile actually mean?
It describes where a child sits among other children, and it is not a mark out of a hundred. Half of all healthy children are below the 50th, and staying there is not a problem. The page says the same thing in its own words and adds the limit: LifeWell does not interpret this chart, does not flag a child, and cannot see the things a clinician weighs alongside it.
Should I worry if the line moves?
The post's answer is that direction matters more than position. A baby who stays on the 20th is typically healthier than one who falls from the 80th to the 30th, and crossing two or more major lines in either direction is on its list of things to raise with your child's doctor. LifeWell will not raise it for you. It plots what you measured.
Why is there no reference curve for head size?
Because LifeWell does not carry the published head-circumference tables, and it says so on the chart rather than quietly leaving the band off. The measurement is still recorded and still plotted, so the shape of it over time is there to read. The comparison against a published table is done by the person who does it properly.
Why do the bands disappear after five years?
The WHO Child Growth Standards cover birth to five years of age, and beyond that a separate reference takes over, one this app does not carry. The measurements keep their line and lose their bands. Nothing is deleted. The chart is only declining to claim a comparison it cannot make honestly.
How should I measure at home?
The post's practical advice is to weigh at the same time of day, before a feed where that is possible, on the same scale every time, and to measure length on a flat surface with the legs fully extended. How often is a question for whoever runs your well-child visits. A curve with one point on it says nothing, which is what LifeWell's own empty state tells you.
Can LifeWell tell me whether my baby is growing well?
No, and it says so before you ask. It plots your measurements against the WHO reference curves and does not interpret them, does not flag a child, and cannot see the examination, the feeding or the family pattern a clinician weighs alongside the numbers. Bring the numbers to the person who examines your child.
By The LifeWell team · updated 2025-10-26
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