Week-by-week library · 21 months old

Month 21

Quick answer

What is my baby up to at 21 months old?

This month, "helping" with chores (even if it slows everything down) is a real developmental win.

Last reviewed 2026-08-28 by This Week Baby editorial team

What's developing

Social

Helping with simple tasks, putting a toy in a bin, carrying a light object, is common and reflects growing independence and a desire to participate.

Motor

Jumping with both feet off the ground together is emerging for many toddlers, a genuinely tricky coordination skill.

Communication

Vocabulary keeps expanding, often with new words appearing daily for some toddlers.

Try this together this week

  • Invite "helping" with an easy, low-stakes task (putting toys in a bin) and let it take longer than doing it yourself.
  • Practice jumping with both feet, even if it starts as more of a hop-stumble.
  • Keep a running mental list of new words this month; it is often a fun one to look back on.
  • Simple matching games (same color, same shape) for early categorization skills.

What parents often notice

The first two-foot jump often looks more like a hard step than an actual jump for a while, which is a completely normal part of learning the movement.

Sourced to

  • Zero to Three, Early Development guides

Last reviewed by the This Week Baby editorial team.

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