Baby Weight Gain Calculator
Track your baby's average weight gain rate since birth, in grams per week and per day.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Your result
175 g/week
Average gain per week
AI explanation
Formula
Total gain = current weight − birth weight. Weekly average = total gain / age in weeksWorked example
Birth weight 3200g, now 4600g at 8 weeks
| Field | Value |
|---|---|
| Birth weight | 3200 |
| Current weight | 4600 |
| Baby's age | 8 |
| Average gain per week | 175 |
| Total gain so far | 1400 |
Assumptions
- Reports the actual observed average gain rate — it does not classify this against a growth percentile chart.
- As a general reference point, WHO growth data suggests roughly 150-200g/week is typical for the first 3 months, tapering afterward — but healthy babies show a wide range.
- Informational only — always discuss growth trends with your pediatrician, who can plot against official WHO/national growth charts.
Frequently asked questions
How much weight should a baby gain per week?
As a general reference, roughly 150-200g/week is typical in the first 3 months, tapering to a slower rate afterward — but individual healthy babies vary meaningfully, so growth chart percentile trends matter more than any single week's number.
Does this tell me if my baby's weight gain is healthy?
No — it only reports the average rate over the period you enter. Your pediatrician assesses healthy growth by plotting weight against age on WHO/national growth charts and tracking the percentile trend over time, not a single average rate.
Why does weight gain slow down after the first few months?
Growth velocity naturally decreases after the rapid early-infancy period as a normal part of development — a slowing rate alone isn't necessarily a concern.
Related calculators
Sources
- WHO Child Growth Standards — World Health Organization. Effective 01-01-2006, reviewed 13-09-2026.
This calculator provides a general estimate only and does not constitute personalized medical advice. Consult your pediatrician to assess whether your baby's growth is on track.
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