Stacking blocks: how the skill grows from 12 to 30 months
Stacking blocks means setting one object on top of another so it stays up. Stacking asks for a steady hand, a well-timed release and two hands sharing the job, the same control a child later uses to set down a cup or build a bridge.
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Stacking blocks: the ladder, step by step
Pick the step that looks most like your child today. The next step and activities that practise it appear below.
No step picked yet. There is no wrong answer: pick the closest one.
Next step: Places one on one. Sets a block on top of another, often letting go too early so it slides off.
Activities that fit this step
- Big Box Tower Topple · 12–18 months · 3–8 min
- Two-Block Tower Trade · 12–20 months · 3–8 min
- Tall Tower, Short Tower · 22–32 months · 5–12 min
Next step: Stacks two or three. Builds a short tower on the floor, steadying the bottom block with the free hand.
Activities that fit this step
- Big Box Tower Topple · 12–18 months · 3–8 min
- Two-Block Tower Trade · 12–20 months · 3–8 min
- Tall Tower, Short Tower · 22–32 months · 5–12 min
Next step: Stacks four to six. Slows down near the top, lines up each block and straightens a wobbly one.
Activities that fit this step
- Two-Block Tower Trade · 12–20 months · 3–8 min
- Tall Tower, Short Tower · 22–32 months · 5–12 min
- Copy-My-Bridge Block Build · 24–34 months · 5–12 min
Next step: Stacks for a purpose. Piles cushions, boxes or cups into a "tower", "cake" or "house" without being shown.
Activities that fit this step
- Two-Block Tower Trade · 12–20 months · 3–8 min
- Tall Tower, Short Tower · 22–32 months · 5–12 min
- Copy-My-Bridge Block Build · 24–34 months · 5–12 min
Top of the ladder (stacks for a purpose). Keep it flexible: offer it in a new place, with a different person or with new materials.
Activities that fit this step
- Two-Block Tower Trade · 12–20 months · 3–8 min
- Tall Tower, Short Tower · 22–32 months · 5–12 min
- Copy-My-Bridge Block Build · 24–34 months · 5–12 min
The stacking blocks ladder
5 steps from the first sign to a flexible skill, covered here from 12 to 30 months. Children move at their own pace: use the steps to see what comes next, not as deadlines.
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Knocks towers down
Swipes at a tower you built, watches it tumble and looks at you to build it again.
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Places one on one
Sets a block on top of another, often letting go too early so it slides off.
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Stacks two or three
Builds a short tower on the floor, steadying the bottom block with the free hand.
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Stacks four to six
Slows down near the top, lines up each block and straightens a wobbly one.
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Stacks for a purpose
Piles cushions, boxes or cups into a "tower", "cake" or "house" without being shown.
When stacking blocks usually shows up
Many children stack two small objects, such as blocks, by about 15 months (a CDC 15-month milestone). Taller towers of four to six pieces usually come over the following year, and towers keep getting straighter toward age 3.
This page follows stacking blocks from 12 to 30 months, a window that spans the 12-month, 15-month, 18-month, 24-month and 30-month CDC checklists.
In the library, 4 activities practise stacking blocks (2 as their main skill), for ages 12 to 34 months. One of them needs no prep and takes 10 minutes or less. By age, they sit closest to steps 1, 2, 4 and 5 of the 5-step ladder.
Related items appear on the CDC checklists for 15 months.
Related milestones
CDC checklist items (paraphrased) that involve stacking blocks. Checklists are for monitoring, not a test.
| Checklist | Milestone |
|---|---|
| 15 months | Builds a stack of two or more small objects, such as blocks. |
Activities that practise stacking blocks
Placed on the closest ladder step by age. By primary domain: 2 fine motor, 1 creativity & pretend and 1 early concepts. Quickest to start: Big Box Tower Topple (3–8 minutes).
Step 1: Knocks towers down
Step 2: Places one on one
Step 4: Stacks four to six
Step 5: Stacks for a purpose
Skills practised alongside
The activities for stacking blocks most often also work on building and constructing (3), cause and effect (1), size words (1), spatial words (1) and taking turns (1). Pairing them keeps practice playful: one activity, several skills.
Practise it inside everyday routines
- Stack kitchen things as well as blocks: plastic tubs, measuring cups and cracker boxes each balance differently.
- Build one block yourself, then hold the next one out and pause so your child chooses whether to stack or topple.
- Count or chant as the tower grows ("one, two, tall!") and let the crash be part of the game.
- Play on a hard, flat surface such as a tray or the kitchen floor; thick rugs topple towers for reasons that have nothing to do with skill.
What to avoid
- Straightening or finishing the tower for your child; a lopsided tower they built themselves is the real practice.
When to mention it to the pediatrician
If your child is not putting one object on top of another by about 15 months, or seems to struggle to grasp and let go with either hand, mention it at the next checkup, and sooner if a skill they had disappears.
Worried about stacking blocks between visits? Call the pediatrician; CDC's free resources also explain how to contact your local Early Intervention program directly. Milestones are for monitoring, not diagnosis.
Frequently asked questions
When do toddlers start stacking blocks?
Many children stack two small objects, such as blocks, by about 15 months (a CDC 15-month milestone). Taller towers of four to six pieces usually come over the following year, and towers keep getting straighter toward age 3. The first step to look for: swipes at a tower you built, watches it tumble and looks at you to build it again.
How can I help my toddler with stacking blocks?
Stack kitchen things as well as blocks: plastic tubs, measuring cups and cracker boxes each balance differently. Build one block yourself, then hold the next one out and pause so your child chooses whether to stack or topple. A good first activity is Big Box Tower Topple (12–18 months).
What should I avoid when practising stacking blocks?
Straightening or finishing the tower for your child; a lopsided tower they built themselves is the real practice.
When should I mention stacking blocks to the pediatrician?
If your child is not putting one object on top of another by about 15 months, or seems to struggle to grasp and let go with either hand, mention it at the next checkup, and sooner if a skill they had disappears. You can also contact Early Intervention yourself.
Related
Monitoring, not medical advice. Talk to your pediatrician about any concern. Our sources and method.