Baby growth
The baby growth tracker logs weight, length (height), and head circumference at each measurement, with an optional percentile field for plotting against standardised growth charts. Most entries come from pediatrician visits — well-baby visits at 1 week, 2 weeks, 1 month, 2 months, 4 months, 6 months, 9 months, 12 months, 15 months, 18 months, and 24 months under the AAP's "Bright Futures" recommended schedule.
You can also log home-measured weight if you have an accurate scale (the bathroom-scale method of "weigh yourself, then weigh holding baby, subtract" works within reason).
What a growth record stores
| Field | Type | Notes |
|---|---|---|
date | timestamp | When the measurement was taken |
ageInDays | number (computed) | Auto-derived from baby's DOB |
weight | number (grams) | Optional |
length | number (cm) | Optional |
headCircumference | number (cm) | Optional |
weightPercentile | number (0–100) | Optional, typically from your pediatrician's printout |
lengthPercentile | number (0–100) | Optional |
headCircumferencePercentile | number (0–100) | Optional |
notes | string | Free text |
measuredBy | string | "Pediatrician at Riverview", "Self at home", etc. |
You don't need to fill all three measurements at every entry — partial entries (just weight, for example, for a weekly home weigh-in) are fine.
Units
| Measurement | Unit |
|---|---|
| Weight | Grams (the database canonical unit) |
| Length | Centimetres |
| Head circumference | Centimetres |
The form accepts imperial input (pounds-ounces, inches) and converts to the canonical metric unit on save:
- 1 lb = 453.592 g
- 1 oz = 28.3495 g
- 1 in = 2.54 cm
Percentiles and growth charts
Percentiles answer "compared to other babies the same age and sex, where does this baby fall?" A weight at the 50th percentile means half of comparable babies weigh less, half weigh more. The 5th percentile is small for age; the 95th is large.
LifeWell stores percentiles as a number 0–100. The app does not compute percentiles from raw measurements automatically — that requires the WHO Child Growth Standards (0–24 months) or CDC growth charts (2+ years) lookup tables, which the app currently does not embed. Get the percentile from your pediatrician's printout or use the WHO's online growth-percentile calculator (who.int/childgrowth), then enter the number in LifeWell.
WHO growth standards are the international reference for breastfed infants 0–24 months; CDC charts are used in the US for older children. The AAP recommends WHO charts for ages 0–24 months and CDC charts for 2+ years.
What growth charts tell you
| Pattern | What it suggests |
|---|---|
| Tracking along the same percentile over time | Normal — the baby is growing at the expected rate for their size |
| Crossing percentiles upward in early infancy | Catch-up growth after slow start, or normal post-newborn weight regain |
| Crossing percentiles downward sustained | Worth discussing with pediatrician — possible feeding adequacy issue, illness, or normal variation |
| Below 3rd percentile or above 97th sustained | Always worth discussing — most healthy babies fall within these bounds |
| Weight-for-length percentile diverging significantly from weight-for-age | Indicator of nutritional status |
Percentile position matters less than trajectory. A baby consistently at the 15th percentile is fine if she's growing along that line; a baby who drops from the 50th to the 10th over two visits warrants a conversation.
Visualisation
The page shows three charts (weight, length, head circumference) over time — your baby's plotted values across all measurements. If percentiles are entered, the chart highlights the percentile next to each point.
A planned future improvement: overlay the WHO percentile bands (5th, 25th, 50th, 75th, 95th lines) so you can see at a glance where the baby's growth sits. Currently the chart shows your data points only; bring your pediatrician's printout to compare.
Worked example
Your 4-month well-baby visit. The pediatrician records:
- Weight: 6.5 kg → enter 6500 g
- Length: 62 cm
- Head circumference: 41.5 cm
- Pediatrician hands you a printout showing 50th / 70th / 60th percentile respectively.
Add a growth record dated today: weight 6500, length 62, head 41.5, percentiles 50 / 70 / 60. Notes: "4-month well-baby visit, Dr Khan, all developmental screens normal."
At the next visit (6 months), add another entry and the chart shows the trajectory.
What this log is not
- Not a percentile calculator. Enter the percentile from your pediatrician's printout.
- Not a growth-failure screen. Trajectory matters; the app does not flag crossing percentiles downward. Your pediatrician's plot of multiple visits is the right tool.
- Not connected to smart scales (Wi-Fi baby scales like Hatch Rest or Withings Baby). Manual entry only.
- Not a substitute for in-person measurement. Length is hard to measure at home; head circumference requires technique. Take pediatrician measurements as the ground truth.
Home weighing — accuracy notes
If you weigh at home between visits, a few practical notes:
- Use a digital scale with 100-g resolution. Bathroom scales (1-kg resolution) are too coarse for infants.
- Weigh nude (or in a consistent outfit) for consistency.
- Same time of day (after a similar amount of time since last feed) for cleaner trend.
- Don't obsess over daily fluctuation — a few hundred grams variation day to day is normal and reflects feed/poop/wet/clothing differences more than real growth.
Weekly trend matters; daily fluctuation doesn't.
Frequently asked
My pediatrician didn't give me a percentile — what do I do? Ask. Or use the WHO online percentile calculator (search "WHO child growth standards calculator"). Or skip the percentile field — the raw weight/length over time still gives you a trajectory.
Should I worry about a low percentile? Position alone is rarely concerning — small babies are often perfectly healthy. Trajectory matters: crossing percentiles downward over two or more visits is the pediatric flag. A consistently 10th-percentile baby growing along the 10th line is fine.
What about premature babies? Use corrected age (chronological age minus weeks born early) for the first 2–3 years. The pediatrician's chart will use corrected age; LifeWell's age computation uses chronological age. Note the correction in your record notes.
Can I export growth data for a specialist? Yes — PDF export from the page. Includes all measurements with percentiles and notes.
Why grams not kilograms? Internal storage is grams to avoid floating-point conversion issues. The form accepts kg input (e.g. type 6.5 → stored as 6500 g) and displays in your selected unit on output.
Where to read next
- Feeding — feeding adequacy is the most common growth driver.
- Milestones — growth and developmental milestones together.
- Diapers — wet-diaper counts as adequate-hydration proxy.
- Overview — baby module map.
Last updated: 2026-05-11 Author: Ahsan Mahmood