If you’re here wondering whether your baby’s weight is “normal,” first take a breath. You’re doing great. Every baby grows at their own pace, but having a simple Infant Weight Chart can be a helpful way to see how things are going. This isn’t about hitting some perfect number—it’s about patterns, progress, and peace of mind.
What Is an Infant Weight Chart?
An Infant Weight Chart is a tool doctors and nurses use to track your baby’s weight over time. It shows the average weight for babies at each age and helps spot trends that might need attention.
It uses “percentiles” to compare your baby’s weight to that of other babies the same age. For example, if your baby is in the 50th percentile, they’re right in the middle—about average. Lower or higher percentiles aren’t good or bad by themselves. What matters more is whether your baby is staying on a steady curve.
Why Tracking Weight Matters
Growth is one of the clearest signs of a baby’s health. It tells you whether they’re getting enough milk, whether their body is absorbing what it needs, and whether there are any red flags to bring up at the next pediatrician visit.
There’s also a connection between very rapid weight gain in infancy and a higher risk of being overweight later in childhood. That doesn’t mean a chubby baby is a problem. It just means that if weight is jumping up percentile lines quickly, it’s worth keeping an eye on things together with your doctor.
How to Read the Infant Weight Chart Without Overthinking It
Reading an Infant Weight Chart doesn’t require a medical degree. Once your baby’s weight is measured, your healthcare provider will plot it on the chart. Here are a few things to keep in mind:
- The 50th percentile is the middle of the curve, not a target.
- Babies usually follow a curve that’s right for them.
- If your baby drops two or more percentile lines, that may be something to ask about.
- Big jumps in weight might also be worth checking in on.
The point isn’t to worry over every ounce. It’s to notice patterns and get support if something seems off.
The Average Infant Weight Chart (0–12 Months)
Here’s a simple, research-based Infant Weight Chart showing the average (50th percentile) weight for boys and girls from birth to 12 months. This is based on WHO standards, which are what most U.S. pediatricians use for babies under two.
Weight Loss and Weight Gain in Babies
Are you worried that your baby is losing weight? You’re not the only one. Most babies will lose weight right after birth. That part is normal. But if the weight loss feels like too much or lasts too long, it’s okay to ask for help.
Some babies lose extra fluid from birth—especially if mom received IV fluids during labor. That’s not a problem in itself. What matters is how your baby is doing overall. If they’re alert, feeding well, making wet diapers, and seem content, they’re probably just fine.
Average Weight Loss and Gain
- It’s normal for babies to lose 5–7% of their birth weight in the first few days. Up to 10% is often seen in exclusively breastfed babies.
- Most will start gaining again by day 5.
- By two weeks, many babies have regained their birth weight.
If your baby loses more than 8%, your care team might take a closer look. If there’s a delay in milk coming in or trouble latching, some babies can lose 10% or more. That’s when extra support can really help.
Once things are going well, breastfed babies tend to gain:
- About 40g (1.4 oz) per day for boys
- About 34g (1.2 oz) per day for girls
Weight gain should not fall below 20g (0.7 oz) a day. If it does, check in with your doctor or a lactation consultant.
What Can Affect Your Baby’s Weight?
There are a lot of factors that influence how much a baby weighs and how quickly they gain:
- Feeding method – Breastfed babies tend to gain weight a little differently than formula-fed babies. Both are okay.
- Birth weight and genetics – Smaller parents often have smaller babies. Big babies can run in families, too.
- Health or feeding issues – Things like reflux, tongue tie, or supply struggles can all affect weight.
- Developmental leaps – Some babies pause weight gain while focusing on new skills like crawling.
Breastfed babies may gain weight faster in the first 2–3 months than formula-fed babies, then slow down. This is totally normal. It’s also why growth charts based on breastfed babies give a more accurate picture. WHO charts are designed with that in mind.
When to Check In With Your Pediatrician
Babies are usually weighed at every well visit in the first year: right after birth, then at 1, 2, 4, 6, 9, and 12 months. If something seems off in between—like your baby isn’t gaining, seems unusually fussy, or suddenly changes feeding habits—don’t wait. Trust your gut.
Also, reach out if:
- Your baby drops more than two percentile curves
- They’re not back to birth weight by 2 weeks
- They seem very sleepy and aren’t waking to feed
Your pediatrician is there to help you make sense of it all.
You’re Not Alone: Common Questions From Other Moms
- Is the 10th percentile bad? No. If your baby has always been small and follows that line, it’s likely just their norm.
- What if my baby is in the 90th? Also okay! But your doctor might check in on feeding habits and growth speed.
- Can babies gain too fast? If weight shoots up several percentile lines quickly, it might be worth a closer look.
- What if my baby isn’t gaining enough? There are many gentle, workable steps that can help. Often it’s a feeding tweak, not a big problem.
A Final Word
Your baby’s weight is just one part of the picture. Growth charts help guide conversations, not define success. If you ever feel unsure, reach out to someone who knows what this journey feels like. There’s no shame in needing help—and no award for doing it all alone.
You’ve got this.
Resources
- Find a breastfeeding support group near you.
- Milkology Breastfeeding Class – Affordable, video-based online course to help you master breastfeeding at your own pace.
References
- 1. World Health Organization Child Growth Standards — Weight-for-Age
World Health Organization (2006) - Infant Growth Patterns and Growth Charts: Term Infant Growth Tools
American Academy of Pediatrics (2022) - Average Baby Weight: Chart and Development
Medical News Today (2019)
