18-Month-Old Toddler Weight & Length Chart
At 18 months, language is about to explode. Most toddlers understand hundreds of words and are saying 15–20 themselves — with a vocabulary spurt coming soon.
Boy — 50th %ile
Girl — 50th %ile
⚖️ Weight by Percentile
| Percentile | 👦 Boy | 👧 Girl |
|---|---|---|
| 5th Percentile | 20 lbs 5 oz | 18 lbs 15 oz |
| 10th Percentile | 20 lbs 15 oz | 19 lbs 10 oz |
| 25th Percentile | 22 lbs 4 oz | 20 lbs 15 oz |
| 50th Percentile (median) | 24 lbs 0 oz | 22 lbs 8 oz |
| 75th Percentile | 25 lbs 13 oz | 24 lbs 0 oz |
| 90th Percentile | 27 lbs 2 oz | 25 lbs 6 oz |
| 95th Percentile | 28 lbs 4 oz | 26 lbs 4 oz |
📏 Length/Height by Percentile
| Percentile | 👦 Boy | 👧 Girl |
|---|---|---|
| 5th Percentile | 2' 7.3" | 2' 6.7" |
| 10th Percentile | 2' 7.6" | 2' 6.9" |
| 25th Percentile | 2' 8" | 2' 7.4" |
| 50th Percentile (median) | 2' 8.4" | 2' 7.8" |
| 75th Percentile | 2' 8.8" | 2' 8.2" |
| 90th Percentile | 2' 9.2" | 2' 8.6" |
| 95th Percentile | 2' 9.5" | 2' 8.9" |
📊 What Does My Baby's Percentile Mean?
A baby at the 50th percentile weighs more than 50% of babies the same age. The 25th–75th percentile range is considered average. Any percentile from the 5th to the 95th is medically normal — your baby's growth curve matters more than their rank. A consistently healthy 10th-percentile baby is thriving; a baby who drops from the 70th to the 30th percentile warrants a conversation with your pediatrician.
🌟 Developmental Milestones
- Runs (somewhat unsteadily)
- Says 15–20 words
- Follows 2-step instructions
- Begins pretend play
Pretend play (feeding a stuffed animal, "talking" on a toy phone) is a sign of growing cognitive complexity. Encourage it — it's foundational for language and social development.
🍼 Feeding at 18 Month Old
Three balanced meals + 2 snacks. 16 oz whole milk per day. Offer vegetables, fruits, proteins, and grains at every meal. Limit juice to 4 oz/day or less.
🚨 Talk to Your Pediatrician If…
- Fewer than 6 words
- Not walking
- Doesn't point to show you things
- Doesn't notice or mind when caregiver leaves
Frequently Asked Questions
How much should an 18-month-old weigh?
WHO median is 10.9 kg (24.0 lbs) for boys and 10.2 kg (22.5 lbs) for girls. Typical range: roughly 9.2–12.8 kg (20.3–28.2 lbs).
What is the vocabulary explosion?
Many toddlers experience a "vocabulary explosion" or "language spurt" between 18–24 months where they begin adding several new words per week. This is supported by improving neural connections.
Should I be worried about autism at 18 months?
The M-CHAT (Modified Checklist for Autism in Toddlers) is a standard screening tool used at 18-month well visits. Early signs to discuss with your pediatrician include limited eye contact, no pointing, and not responding to name.
How much TV time is OK for an 18-month-old?
The AAP recommends no screen time except video chat before 18–24 months. After 18 months, high-quality educational programming in small amounts (30 min/day) watched with a caregiver is the guideline.