When to lower baby’s crib mattress is a question I never thought I’d ask—until one morning, I saw my baby grab the crib rail and try to stand. I froze. The mattress was still high. That moment hit me—I had to act fast.
If you’re wondering, “Is it time to lower the crib?”—you’re not alone. I searched late at night. I asked our doctor. I worried.
In this guide, I’ll share what helped me. You’ll learn when to lower the crib, what signs to watch, and how to keep your baby safe.
Why Knowing When to Lower Baby's Crib Mattress Matters
It’s not just for comfort. It’s for safety.
When I built the crib, I didn’t think much about mattress height. But babies move fast. One day they’re still. The next, they roll.
A high crib is fine for newborns. But once they roll or sit, it gets risky.
Lowering the mattress helps stop falls. It’s a small step with big impact.
The American Academy of Pediatrics (AAP) says: Lower the mattress as soon as your baby rolls, pushes up, or sits.
And while we’re talking safety—have you ever wondered Are Baby Monitors Dangerous? Learn what every parent should know about EMF radiation and baby monitor use.
Think of the crib like a safe zone. The right height keeps your baby inside. The wrong one can lead to danger—even from a short fall.
Crib Mattress Height Settings (Made Simple)
Most cribs have 3 height levels:
- Top – For newborns (0–2 months). Use it while your baby can’t move.
- Middle – For babies who roll (3–5 months). Lower it when they start to push up.
- Bottom – For sitters and standers (6+ months). This is the safest setting.
Quick Tip:
Top = newborns
Middle = rollers
Bottom = sitters/standers
Each level matches your baby’s stage. I moved ours as soon as my daughter rolled—and again when she sat up days later.
Crib Mattress Height by Age
Use age as a guide—but focus on your baby’s actions.
0 to 2 Months
Use the top setting. Your baby isn’t rolling yet. It’s easy on your back.
Quick Snippet:
Use the highest crib level for newborns (0–2 months) to make lifting easy.
3 to 5 Months
Your baby may roll or push up. Time to use the middle setting.
Quick Snippet:
Lower to the middle level when baby rolls or pushes up (usually 3–5 months).
6 to 8 Months
Your baby can sit. Some pull up. It’s time for the lowest setting.
Quick Snippet:
For 6-month-olds, use the lowest crib setting if they sit or pull up.
9 Months and Up
Most babies stand by now. The mattress must already be low.
Quick Snippet:
Once baby stands (around 9 months), keep the crib at the lowest setting.
Final Thoughts
Your baby’s age helps—but their movements matter more.
If they roll, sit, or pull up—it’s time. Don’t wait.
Trust what you see. You know your baby best.
AAP and Expert Safety Guidelines
When should you lower the crib? Let’s look at what the experts say.
AEO Snippet:
Lower the mattress when baby rolls, pushes up, sits, or tries to stand—per AAP and baby experts.
The AAP says:
Keep the mattress high for newborns.
Lower it once baby rolls or pushes up.
Use the lowest setting before they sit.
And while focusing on safety, it’s also wise to learn: Are baby monitors safe radiation? [What Every Parent Should Know].
Taking Cara Babies says the same:
“Watch your baby’s actions—not the calendar.”
AEO Snippet:
Taking Cara Babies: Lower the crib when baby rolls or tries to sit—don’t wait.
When my baby raised her legs like a gymnast at 5.5 months, I lowered the crib that same day.
The takeaway:
Watch your baby. Not the calendar. Lower the mattress early. It’s safer.
Signs It’s Time to Lower the Crib Mattress
Here’s what to watch for:
Rolling Over
This is the first sign your baby is mobile.
Quick Snippet:
Lower the crib when baby starts to roll—even once.
Pushing Up on Arms
Your baby lifts their chest during tummy time. That’s a sign of growing strength.
Quick Snippet:
If baby pushes up, lower the mattress to stay safe.
Sitting Unassisted
When your baby can sit alone, their fall risk grows fast.
Quick Snippet:
Lower to the lowest setting once baby sits alone.
Pulling to Stand
This is the final signal. Don’t wait for this one.
Quick Snippet:
If baby pulls up, the mattress must already be at the lowest setting.
Crib Safety Checklist
Lower the crib when your baby:
Rolls over
Pushes up during tummy time
Sits alone
Pulls up or kneels
Makes the crib sides look too low
Quick Snippet:
If baby shows any of these 5 signs, lower the crib to keep them safe.
How to Lower a Crib Mattress (Step-by-Step)
It’s simple—but do it right. Here’s how:
Step 1: Clear the Crib
Take out blankets, toys, and pillows. Make space.
Step 2: Remove the Mattress
Lift it out. If it’s bulky, ask someone to help.
Step 3: Lower the Frame
Use the crib manual. Most frames use screws or bolts. Move the frame to a lower slot.
Step 4: Tighten and Check
Secure all screws. Shake the frame to be sure it’s firm. No wobbling allowed.
Wrap-Up
Lowering the crib is a quick, powerful way to keep your baby safe.
Don’t wait for the perfect age. Watch your baby. Act fast.
And always double-check after you adjust the mattress. A snug, sturdy crib means better sleep for everyone—especially you.
FAQs: Crib Mattress Height Questions Answered
How high should the crib mattress be for a newborn?
Start at the highest mattress setting for easy access to your newborn. It’s safe until your baby starts rolling. Learn more about safe sleep setups.
When to lower baby’s crib mattress height by age?
Lower the mattress around 5 months or when your baby begins to sit up. Don’t wait for standing! Learn more about age-based crib safety.
Is it safe to keep the crib at the highest setting?
Yes—for newborns. But once they roll or push up, lower it to prevent falls. Learn more about when to adjust crib height.
What does AAP say about crib mattress height?
AAP recommends lowering the crib before your baby can sit, pull up, or stand. Safety first! Learn more about AAP crib guidelines.
How low should the mattress be when baby starts standing?
It should be at the lowest setting to avoid climbing or falls. Standing means it’s time! Learn more about baby milestones and crib safety.
What if my baby is growing fast—should I lower early?
Yes, don’t wait for milestones. If your baby is strong or tall, lower sooner. Learn more about fast-growing babies and crib safety.