Adjusted Age Calculator for Preemies
Calculate your premature baby's adjusted age by subtracting weeks born early from chronological age. Free preemie age tool.
Developmental Milestones Calculator
Track your child's developmental milestones by age. CDC-based motor, language, cognitive, and social milestones from 2 months to 3 years.
months
Age Stage⧉
12 months
12.00 months old
Total Milestones⧉
12
Across 4 domains for this stage
Stage Progress⧉
100%
Through the 12 months window
Motor Skills⧉
3 milestones
Pulls to stand, cruises along furniture
Language⧉
3 milestones
Says 1-2 words (mama, dada)
Cognitive⧉
3 milestones
Puts something in a container
Social / Emotional⧉
3 milestones
Plays pat-a-cake
Next Stage⧉
18 months
12 milestones ahead
Domain Progress
Motor Skills
3 skills
Language & Communication
3 skills
Cognitive Development
3 skills
Social & Emotional
3 skills
Milestones by 12 months
| Domain | Expected Milestones |
|---|---|
| Motor Skills | Pulls to stand, cruises along furniture |
| May take first steps | |
| Picks up small objects (pincer grasp) | |
| Language & Communication | Says 1-2 words (mama, dada) |
| Waves bye-bye | |
| Responds to simple requests | |
| Cognitive Development | Puts something in a container |
| Finds hidden things | |
| Pokes with index finger | |
| Social & Emotional | Plays pat-a-cake |
| Cries when parent leaves | |
| Is shy or nervous with strangers |
Adjacent Stages
| Stage | Motor | Language | Cognitive | Social |
|---|---|---|---|---|
| 9 months ✓ | Sits without support | Makes different sounds like "mamamama" | Looks for hidden toys (object permanence) | May be clingy with familiar adults |
| 12 months ★ | Pulls to stand, cruises along furniture | Says 1-2 words (mama, dada) | Puts something in a container | Plays pat-a-cake |
| 18 months → | Walks independently | Tries to say 3+ words besides mama/dada | Copies you doing chores | Shows affection |
Full Milestone Timeline (All Stages)
| Age | Motor | Language | Cognitive | Social |
|---|---|---|---|---|
| 2 months | Lifts head during tummy time | Makes cooing sounds | Watches you as you move | Social smile |
| 4 months | Holds head steady unsupported | Babbles with expression | Reaches for toys | Laughs out loud |
| 6 months | Rolls from tummy to back | Responds to own name | Puts things in mouth to explore | Knows familiar people |
| 9 months | Sits without support | Makes different sounds like "mamamama" | Looks for hidden toys (object permanence) | May be clingy with familiar adults |
| 12 months ★ | Pulls to stand, cruises along furniture | Says 1-2 words (mama, dada) | Puts something in a container | Plays pat-a-cake |
| 18 months | Walks independently | Tries to say 3+ words besides mama/dada | Copies you doing chores | Shows affection |
| 2 years | Runs | 50+ words, 2-word phrases | Plays with more than one toy at a time | Notices when others are hurt |
| 3 years | Climbs well | Simple sentences, asks "why" | Draws a circle | Takes turns |
Planning notes, formulas, and examples
About the Developmental Milestones Calculator
The CDC provides evidence-based developmental milestones that most children reach by certain ages. These cover four domains: gross/fine motor skills, language/communication, cognitive skills, and social/emotional development.
Milestones are markers, not deadlines. Children develop at different rates, and a range of timing is normal. However, consistently missing milestones can be an early sign of developmental delays, and early intervention leads to better outcomes.
This calculator shows expected milestones for your child's age across all four developmental domains. Use it to celebrate progress and identify areas to discuss with your pediatrician.
When This Page Helps
The CDC revised its milestone guidance, and many parents still work from older charts. This page provides a concise age-based checklist that is easier to review before a pediatric visit.
How to Use the Inputs
- Enter your child's age in months.
- View the milestones expected by this age.
- Review all four developmental domains.
- Note any areas where your child hasn't reached milestones.
- Discuss concerns with your pediatrician at the next well-child visit.
Formula used
Based on the CDC milestone framework used on this page:
2 months: social smile, lifts head
4 months: babbles, reaches for toys
6 months: sits without support, responds to name
9 months: crawls, says "mama/dada"
12 months: pulls to stand, 1-2 words
18 months: walks, 10+ words
24 months: runs, 50+ words, 2-word phrases
36 months: climbs, simple sentencesExample Calculation
Result: Pulls to stand, waves bye-bye, 1-2 words, imitates actions
By 12 months, most babies can pull to a standing position, cruise along furniture, say 1-2 words (like "mama" or "dada" with meaning), wave bye-bye, and imitate simple actions like clapping.
Tips & Best Practices
- Milestones represent what MOST children do by a certain age — ranges are normal.
- Premature babies should use adjusted age for milestones until age 2.
- Talk to your baby often — language exposure drives speech development.
- Tummy time strengthens muscles needed for crawling and walking.
- If you're concerned about any domain, don't wait — ask your pediatrician.
- The CDC's free Milestone Tracker app is a great companion tool.
The Four Developmental Domains
Gross and fine motor: physical movements from head control to running and drawing. Language and communication: from cooing to sentences. Cognitive: problem-solving, learning, and understanding. Social-emotional: bonding, playing with others, and managing feelings.
The CDC Milestone Update
The CDC revised milestones to reflect what 75% of children achieve by each age (previously 50%). This means the newer milestones represent later ages, reducing unnecessary worry while still identifying children who need evaluation.
Red Flags at Any Age
Loss of skills previously mastered, no response to name by 12 months, no pointing or gesturing by 12 months, no words by 16 months, no 2-word phrases by 24 months, and any loss of speech or social skills at any age. These warrant immediate pediatric evaluation.
Sources & Methodology
Last updated:
Frequently Asked Questions
Missing one milestone isn't cause for alarm — children develop at individual rates. If your child misses several milestones or regresses (loses skills they had), contact your pediatrician. Early intervention services are free in most states.
Most babies walk independently between 9-18 months, with the average around 12 months. Late walking (up to 18 months) is usually normal. If a child isn't walking by 18 months, discuss with your pediatrician.
First intentional words ("mama," "dada" with meaning) typically appear around 12 months. By 18 months, most toddlers say 10+ words. By 24 months, expect 50+ words and 2-word phrases.
On average, girls tend to reach some milestones slightly earlier than boys, particularly in language. However, the individual variation within each gender is much larger than the difference between genders.
Early intervention is a federally funded program (Part C of IDEA) providing free therapy services for children 0-3 with developmental delays. Services include speech, physical, and occupational therapy. Contact your state's early intervention program for an evaluation.
Focus on your child's individual progress rather than comparing to others. Children develop different skills at different rates. What matters is steady progress across all domains, not being first to reach any particular milestone.
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