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Almost all babies lose weight in the first few days as they pass fluid and meconium and feeding gets going. A loss of 5–7% is typical; more than 10% needs a feeding review.
Enter the birth weight, today's weight and the baby's age in days to see the percentage change, whether it is in the normal range, and the gain to expect in the coming months.
| Birth Weight | 3.4 |
| Current Weight | 3.15 |
| Weight Unit | kg |
| Baby's Age | 3 days |
| Change from birth weight | -7.4% (-250 g) |
| Assessment | 7–10% loss — get a feeding check |
| Lowest normal weight (−10%) | 3,060 g |
| Should regain birth weight by | day 10–14 |
| Expected weight at 4–5 months (about double) | 6.8 kg |
| Expected weight at 12 months (about triple) | 10.2 kg |
-7.4% (-250 g) — 7–10% loss — get a feeding check.
Try this example →| Birth Weight | 7.5 |
| Current Weight | 8.2 |
| Weight Unit | lb |
| Baby's Age | 21 days |
| Change from birth weight | +9.3% (+318 g) |
| Assessment | Above birth weight |
| Lowest normal weight (−10%) | 3,062 g |
| Should regain birth weight by | day 10–14 |
| Average gain since day 10 | 29 g a day (202 g a week) |
| Expected weight at 4–5 months (about double) | 6.8 kg |
| Expected weight at 12 months (about triple) | 10.21 kg |
+9.3% (+318 g).
Try this example →Up to 7% is common and up to 10% is the usual upper limit, reached around days 3–4.
By 10–14 days old.
About 150–200 g a week in the first 3 months, 100–150 g from 3–6 months and 70–90 g from 6–12 months.
Around 4–5 months, and triples it by about 12 months.