Baby Weight GainWhat to Expect Month by Month
Normal baby weight gain from newborn to 12 months. Know what to expect and when to talk to your pediatrician.
The Most Important Thing
Consistent growth along their own curve matters more than hitting exact numbers. Every baby is different. Your pediatrician looks at the pattern over time, not single measurements.
Average Baby Weight by Month
| Age | Boys (50th %ile) | Girls (50th %ile) | Notes |
|---|---|---|---|
| Birth | 7.5 lbs (3.4 kg) | 7.3 lbs (3.3 kg) | Average. Normal range: 5.5-10 lbs |
| 1 Month | 9.9 lbs (4.5 kg) | 9.4 lbs (4.3 kg) | Gaining 5-7 oz per week |
| 2 Months | 12.3 lbs (5.6 kg) | 11.5 lbs (5.2 kg) | About 1.5-2 lbs/month |
| 3 Months | 14.1 lbs (6.4 kg) | 13.0 lbs (5.9 kg) | Often doubling birth weight soon |
| 4 Months | 15.4 lbs (7.0 kg) | 14.2 lbs (6.4 kg) | Growth rate starting to slow |
| 6 Months | 17.6 lbs (8.0 kg) | 16.1 lbs (7.3 kg) | Starting solids may begin |
| 9 Months | 20.0 lbs (9.1 kg) | 18.3 lbs (8.3 kg) | About 1 lb/month now |
| 12 Months | 21.9 lbs (9.9 kg) | 20.2 lbs (9.2 kg) | Usually tripled birth weight |
Based on WHO growth standards. Individual babies vary significantly.
Normal Weight Gain Expectations
First few days
Lose 5-7% of birth weight (up to 10% is normal)
Losing fluid and meconium; milk not fully in yet
By 10-14 days
Should regain birth weight
Milk supply established; feeding patterns developing
0-3 months
Gain 5-7 oz (150-200g) per week
Rapid growth phase; exclusively on milk/formula
3-6 months
Gain 4-5 oz (110-140g) per week
Growth rate naturally slows somewhat
6-12 months
Gain 2-4 oz (60-110g) per week
More active; starting solids; growth continues to slow
When to Call Your Pediatrician
Not regained birth weight by 2 weeks
Contact pediatrician immediately
Losing weight after initial loss period
Same-day call to pediatrician
Fewer than 6 wet diapers after day 5
May indicate inadequate feeding
No weight gain for 2+ weeks
Schedule weight check
Falling off growth curve
Discuss with pediatrician at next visit
Persistent green watery stools
May indicate feeding issue; discuss with doctor
Feeding Tips for Healthy Weight Gain
Feed on demand in early weeks
8-12 times per day for breastfed babies; every 2-3 hours
Watch baby, not the clock
Hunger cues: rooting, hands to mouth, fussiness (crying is late sign)
Let baby finish one breast first
Hindmilk (at end) is fattier and helps with weight gain
Formula: follow mixing instructions exactly
Under-diluting causes dehydration; over-diluting reduces calories
Don't force finish bottles
Baby knows when they're full. Forcing can lead to overfeeding
Track wet/dirty diapers early on
Good output = good input before weight checks confirm
Frequently Asked Questions
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