Stacks at least two small objects (like blocks)

What is this milestone?

Hand-eye coordination and planning

Using careful hand-eye coordination, your toddler can balance one block or object directly on top of another without it immediately falling over.

Why it matters

Stacking requires precision, depth perception, and spatial awareness. It also introduces basic concepts of gravity, balance, and problem-solving as they figure out how to align the blocks.

What to expect leading up to it

At first, they will be much more interested in knocking down towers you build than building their own. Then they will tentatively try to balance two blocks, which requires them to learn the exact moment to release their grasp.

How to encourage and support it

Provide large, lightweight blocks (like chunky wooden blocks or large plastic bricks). Build towers together and cheer when they successfully add a piece. And yes, knocking them down is still half the fun!

When to talk to your doctor

Mention it if your child cannot stack two or three blocks by around 21 months, cannot pick up and release small objects deliberately, or seems to use one hand almost exclusively. And at any age, if your baby loses a skill they already had, tell your pediatrician that week.