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Babies usually grow along a percentile line. Enter the birth weight, today's weight and the date of birth to see the weight your baby would be on the same percentile as at birth, the average gain per day, and whether the percentile has changed.
Dropping across two major percentile lines is a reason to see your doctor, but small changes in the first 2–3 months are common as babies settle onto their own curve.
| Sex | Boy |
| Date of Birth | 1 Jun 2026 |
| Date Weighed | 1 Oct 2026 |
| Birth Weight | 3.2 |
| Current Weight | 6.0 |
| Weight Unit | kg |
| Born at (weeks of pregnancy) | 40 weeks |
| Assessment | Crossed down one percentile line — watch the trend and discuss at the next check-up |
| Expected weight now (same percentile as at birth) | 6.77 kg |
| Current weight | 6 kg — 9th percentile |
| Birth weight | 3.2 kg — 38th percentile |
| Weight gained | 2.8 kg since birth (23 g a day on average) |
| Age | 4 months 0 days |
| Typical gain at this age | 15–20 g a day (about 100–150 g a week) |
Crossed down one percentile line — watch the trend and discuss at the next check-up; expected 6.77 kg.
Try this example →About 150–200 g a week for the first 3 months, 100–150 g from 3 to 6 months, then 70–90 g.
Around 4–5 months, and triple it by about 12 months.
Not usually if feeding well and growing steadily; crossing two lines downward needs a check-up.