21-month-old baby milestones: Development, growth, speech, language, and more

Nikki Stevenson

Nikki Stevenson

Nikki is a parenting writer and a mom to three wild boys who keep her on her toes (and occasionally make her question her sanity). With over 15 years of experience in the parenting industry, she has more tips and tricks than Mary Poppins on speed dial. When she's not typing away at her keyboard, you can find her sipping on coffee, hiding in the bathroom for five minutes of...
Medically reviewed Medically reviewed by Faith Hobson
Updated on Oct 22, 2024 · 12 mins read
21-month-old baby milestones: Development, growth, speech, language, and more

Your baby is now a 21-month-old, and the journey through toddlerhood is well underway.


This is an exciting time filled with rapid development and discovery. Your little one is growing physically and making strides in language, social skills, and cognitive abilities.

Your 21-month-old toddler is becoming more independent and adventurous. They are eager to try new things and often surprise you with their creativity and problem-solving skills. This age period is also marked by an increasing ability to communicate, verbally and non-verbally, making interactions more fun, engaging and sometimes more challenging.

In this guide, we’ll explore which milestones you can expect your kids to see this month, including physical development, sleep needs, feeding habits, and more. This encompasses tips and activities to support your child’s growth and ensure they continue to thrive.

21-month-old physical milestones


At 21 months, your toddler displays impressive physical feats, continuing to develop their motor abilities. This stage is marked by enhanced coordination, balance, and strength, which contribute to their growing independence.

Core strength: Your 21-month-old toddler’s core muscles are becoming stronger, improving their posture and stability. This development allows them to sit upright for longer periods without support and engage in activities like bending down to pick up objects and standing back up easily.

Running and climbing: While walking was a major milestone, many 21-month-old toddlers now run confidently. They might also show a keen interest in climbing – whether onto furniture, playground equipment, or even attempting to scale small obstacles. These activities help build muscle strength and coordination.

Kicking and throwing: Enhanced leg and arm strength enable 21-month-old toddlers to kick a ball more accurately and throw objects with better aim. These activities are great for developing both gross and fine motor abilities, as well as hand-eye coordination.

Fine motor skills: Your child’s dexterity is improving, allowing for more precise movements. They might enjoy activities like stacking small blocks, turning book pages one at a time, and using crayons or markers to make more controlled marks on paper.


Social and emotional development


This stage is marked by many toddlers showing an increasing awareness of their own feelings and the feelings of others, which can sometimes lead to surprising (and super cute) moments of empathy and compassion.

  • Independence and autonomy: Your 21-month-old toddler is beginning to assert their independence more forcefully. They may insist on doing things themself, such as dressing, feeding, or choosing toys. This growing autonomy is crucial to their development and helps build confidence and self-esteem.
  • Emotional expression: At this age, 21-month-old toddlers are better at expressing their emotions. Although, they might still struggle to manage them. You may notice more frequent and intense displays of happiness, frustration, anger, or sadness. Their emotional intelligence may benefit from helping your child name and understand their feelings.
  • Empathy and social awareness: Your child might start to show signs of empathy, such as comforting a crying peer or offering to share a toy. They are beginning to understand that others have feelings too – a significant milestone in social development.
  • Parallel play: While your 21-month-old toddler may not yet engage in cooperative play, they enjoy playing alongside other children. This parallel play is an important step towards more interactive social interactions and teaches them about sharing and turn-taking.
  • Routine and security: Consistency and routine provide a sense of security for many toddlers. They feel more comfortable and confident when they know what to expect from their daily schedule. Maintaining regular meal times, nap times, and bedtime routines can help them feel secure and reduce anxiety.

21-month-old baby weight and length


Tracking your 21-month-old toddler’s growth is essential to ensure they are developing properly. At 21 months, there is a broad range of what is considered typical for weight and length as each child grows at their own pace. Here’s a look at the general standards and what to expect:

Understanding growth patterns

  • Individual variation: Every child grows at a unique rate, influenced by genetics, nutrition, and overall health. Regular check-ups with your healthcare provider are crucial to monitor your child’s growth and address any concerns early.
  • Growth charts: Healthcare providers use growth charts, such as those provided by the World Health Organisation (WHO), to compare your child’s growth with established benchmarks. These charts help track growth patterns over time.

Average weight and length

  • Boys: At 21 months, boys typically weigh between 11.3 kg and 13.5 kg and measure between 82.3 cm and 86.7 cm in length.
  • Girls: Girls generally weigh between 10.8 kg and 13.1 kg and range from 80.9 cm to 85.6 cm in length.

Monitoring growth at home

  • Regular measurements: You can monitor toddler development by regularly measuring their height and weight at home. Use a growth chart to plot these measurements and observe trends.
  • Healthy growth indicators: Consistent growth along a percentile line on the growth chart indicates healthy development. Sudden changes in growth patterns can be discussed with your healthcare provider.

Professional guidance

  • Check-ups: Regular visits to the paediatrician ensure your 21-month-old child’s development is on track. During these visits, the healthcare provider will measure your child’s height and weight and compare them to standardised growth charts.
  • Nutritional needs: Proper nutrition plays a vital role in healthy growth. Ensure your toddler’s diet includes a variety of foods from all food groups to support their development.

21-month-old feeding milestones


At this point in life, your toddler is developing more sophisticated eating habits and preferences.

Self-feeding skills

Improved dexterity: Your toddler’s fine motor abilities are more refined, allowing them to see new food and handle utensils with better control. They can now scoop food with a spoon and stab pieces with a fork, even being able to drink from a cup as well.

Finger foods: They continue to enjoy finger foods, which are easy to pick up and eat. This new skill promotes independence and helps develop their pincer grasp.

Balanced diet

Variety of foods: At 21 months, it’s essential to offer a variety of foods from all food groups to ensure they receive balanced nutrition. This includes fruits, vegetables, grains, proteins, and dairy.

Introducing new flavours: Most toddlers can be picky eaters, but introducing new flavours and textures regularly can help broaden their palate. Try incorporating a mix of familiar and new foods to make mealtimes interesting.

Portion sizes: Serve small, manageable portions appropriate for their age. A good rule of thumb is to offer about 1/4 to 1/2 of an adult-sized portion.

Nutritional needs

Iron and protein: Ensure your child gets enough iron and protein to support their rapid growth. Good sources include lean meats, beans, lentils, and fortified cereals.

Calcium and vitamin D: Dairy products like milk, cheese, and yogurt are important for bone development. If your child is lactose intolerant, look for fortified alternatives.

Healthy fats: Include sources of healthy fats such as avocados, nuts, and fish, which are crucial for brain development.

Meal routine

Regular meal times: Establishing a regular schedule with a consistent meal and snack schedule helps regulate your toddler’s appetite and provides structure. Aim for three main meals and 2-3 healthy snacks per day.

Hydration: Encourage your child to drink water throughout the day. Limit sugary drinks and juices, which can contribute to tooth decay and unnecessary calorie intake.

Handling picky eating

Patience and persistence: It’s common for toddlers to go through phases of picky eating. Continue offering a variety of foods without pressuring them to eat. Repeated exposure can eventually lead to acceptance.

Role modelling: Children often mimic their parents’ eating habits. Eating a balanced diet yourself and showing enthusiasm for healthy foods can encourage your toddler to try them as well.

21-month-old sleep milestones


Overcoming sleep regression

Sleep regression is common in toddlers at around 21 months, often due to developmental changes, moving into a big kid bed, and increased independence. It can disrupt your 21-month-old toddler’s usual sleep patterns, making it harder to fall asleep.

Strategies to overcome sleep regression

  • Maintain a consistent routine: Stick to a calming bedtime routine with activities like a warm bath, reading a book, and some quiet time.
  • Create a sleep-friendly environment: Ensure the room is quiet, dark, and cool. Use a favourite blanket or stuffed animal for comfort to help them fall asleep faster.
  • Reassure and comfort: Spend a few extra minutes with your child before bed to ease any separation anxiety.
  • Manage nighttime awakenings: Keep interactions brief and calm, avoiding stimulating activities, especially during nighttime sleep.

Example sleep schedule

Morning:

  • 7:00 AM: Wake up and breakfast
  • 9:30 AM: Morning snack
  • 11:30 AM: Lunch

Afternoon:

  • 12:30 PM: Afternoon Nap time (1.5-2 hours)
  • 2:30 PM: Wake up and afternoon snack
  • 5:30 PM: Dinner

Evening:

  • 6:30 PM: Quiet playtime
  • 7:00 PM: Bath time
  • 7:30 PM: Storytime
  • 8:00 PM: Bedtime

This sleep schedule provides a balanced sleep routine, ensuring your 21-month-old child gets adequate rest while accommodating their developmental needs. Adjust the timing as needed to fit your child’s specific patterns and preferences.

Additional Behaviours at 21 Months


At 21 months, your toddler is developing rapidly and exhibiting new behaviours that reflect their new environment and growing independence, curiosity, and cognitive abilities. Here are some key behaviours due to your little one’s development and age:

  • Explorative play: Your 21-month-old toddler is increasingly curious and loves to explore their surroundings. They may enjoy activities that involve sorting, stacking, and problem-solving. Providing safe and stimulating environments encourages this exploratory behaviour.
  • Tantrums and emotional outbursts: Emotional regulation is still developing, so tantrums can be common, especially when they feel frustrated or overwhelmed. This is a normal part of development as they learn to navigate their emotions.
  • Imitation and role play: Your child is likely to imitate adults and older children, engaging in role-play such as pretending to cook, clean, or talk on the phone. This type of play helps them understand the world around them and develop social skills.
  • Increased vocabulary: Language skills are expanding rapidly. Your toddler might start using two-word phrases and have a vocabulary of around 50 words or more. Encourage this development by talking to them often, reading books, and singing songs together.
  • Social interaction: While they may still engage in parallel play, your child will begin to show more interest in playing with children of the same age. Encouraging social activities and playdates can help them develop important social skills.

Tips for managing these behaviours


  • Stay patient: Tantrums and emotional outbursts are a normal part of life as your child develops. Understanding this can help you stay calm and patient. Offer comfort and support, and try to understand the underlying cause of their frustration.
  • Encourage imitative play: Provide opportunities for role play by offering toys and props that mimic real-life objects. This can help them develop cognitive and social skills.
  • Support language development: Engage in conversations with your toddler, even if their responses are limited. Reading and singing can also significantly boost their language skills.
  • Foster social skills: Arrange regular playdates and encourage sharing and cooperative play. Modelling positive social interactions yourself can also be very effective.

Activities for supporting development


Engaging your 21-month-old in activities that promote development is essential for their growth. Here are some activities tailored to how parents support kids with their physical, cognitive, and social skills:

Physical development

  • Obstacle courses: Set up a simple obstacle course in your living room or backyard. This can include pillows to climb over, tunnels to crawl through, and softballs to kick. These activities help develop gross motor abilities and coordination.
  • Dance and movement: Play music and encourage your toddler to dance. Dancing helps improve balance, coordination, and rhythm. It’s also a fun way to burn off energy, even when done with silly songs.
  • Outdoor play: Take your child to a playground where they can run, climb, and slide. Outdoor play supports physical fitness and allows them to explore different textures and terrains.

Cognitive development

  • Puzzles and shape sorters: Simple puzzles and shape sorters are excellent for developing problem-solving skills and hand-eye coordination. Start with larger pieces that are easier to handle before moving on to small objects.
  • Reading Together: Read books with colourful pictures and simple stories. Ask questions about the pictures to encourage your child to think and respond to new words, which enhances language and comprehension.
  • Building Blocks: Playing with blocks helps develop spatial awareness and fine motor abilities. Encourage your child to build towers or create simple structures.

Social and emotional development

  • Role-playing games: Provide toys like kitchen sets, dolls, or toy phones to encourage role-playing. This helps your child understand social roles and develop empathy.
  • Playdates: Arrange regular playdates with other children. This provides opportunities for social interaction, sharing, and cooperative play.
  • Emotion cards: Use cards with different facial expressions to help your child recognise and name their emotions. Discuss each emotion and what might cause it, which aids in emotional literacy.

Sensory play

  • Sand and water play: Set up a small sandpit or water table where your child can scoop, pour, and mix. Sensory play enhances fine motor skills and provides a calming activity.
  • Play dough: Create or buy play dough and let your child squish, roll, and mould it into shapes. This tactile activity is great for sensory development and fine motor abilities.

Checklist for this month


To ensure your 21-month-old is thriving, here’s a focused checklist for this month:

  • Schedule a regular health check-up at the doctor’s office.
  • Ensure vaccinations are up to date.
  • Maintain a consistent sleep schedule.
  • Establish a calming bedtime routine.
  • Offer a variety of foods from all food groups.
  • Encourage self-feeding with utensils.
  • Engage in physical activities like running and climbing.
  • Provide cognitive stimulation with puzzles and books.
  • Arrange playdates to support social skills.
  • Childproof your home for safe exploration.
  • Ensure regular handwashing for disease control and keep toddler’s teeth clean.

Sources


Pampers, Your 21-Month-Old’s Development and Milestones, May 2023.

Nutrition Australia, Helping kids to become great eaters, August 2021.

Sleep Foundation, Children and Sleep, November 2023. 

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