When to Lower the Crib Mattress

Are you wondering when to lower the crib mattress? Let me help. I’ll explain when to lower the crib mattress, crib height limits, when to transition out of the crib, and other crib safety standards. 

When do you lower the crib mattress?#anchor

It’s time to lower the crib mattress when your little one starts sitting independently. Even though many cribs have a middle setting, the best option is to move the crib mattress to the lowest possible position as soon as your baby can sit. Even if your little one isn’t yet standing, this is the safest option. 

Here’s why: An infant’s head is much heavier than their body, making them top-heavy. We want the crib rail to be at or above mid-chest height to prevent toppling out of the crib when they start pulling to stand. 

What is the recommended crib height limit?#anchor

The American Academy of Pediatrics⁽¹⁾ recommends that your child should be moved from their crib to a toddler bed once the top of the crib rail is lower than mid-chest (or nipple level) height. This typically occurs when an infant reaches about 35 inches. 

How do I put my baby down in a lowered crib without waking them?#anchor

If you are finding it difficult to lay your sleeping baby down into the crib without waking them up, my best advice is to put your baby in the crib awake! 

Awake? Yes! When your baby is able to fall asleep independently in the crib, they typically sleep better (think: longer naps and more consolidated night sleep). 

How do I lower the crib mattress to the floor?#anchor

It’s not always an option to lower the crib mattress to the floor. In some cases, it just isn’t safe. Refer to the manufacturer’s guidelines for your specific crib model to determine if it’s possible to lower your crib mattress to the floor. 

If you’re asking this because you have a little one climbing out of the crib, know that you have options.

1. Use a sleep sack. This will make it more difficult for your little one to lift a leg over the side of the crib.

2. Move the crib. Try pushing the crib into a corner of the room where it can block two of the sides.

3. Turn the crib around. Some cribs have a taller “back.” If this is your crib, try turning the crib so that the “back” is now the front. 

4. Use the monitor. Use a “two-way talk” baby monitor and firmly say, “NO” if you see your little one beginning to crawl out of the crib.

If you simply cannot keep your little one contained and safe in the crib, my Ultimate Guide to the Toddler Bed Transition can help.

When is it time to transition out of the crib?#anchor

Most toddlers will be ready to transition out of the crib around 2-4 years old. However, current research shows that waiting until your child is closer to 3 can make that transition easier.⁽²⁾

Transitioning your toddler out of the crib too early is one of the most common reasons for toddler sleep struggles, so if your little one is safe in the crib, try not to rush that transition.

Crib and crib mattress safety standards#anchor

Choosing a crib and crib mattress that meets current safety standards is an important step in creating a safe sleep environment for your baby. These safety standards include:

• A firm, flat mattress

• No gaps between the mattress and the crib

• No bumpers or crib tents

• Snuggly fitted sheets on the mattress

• Slats no more than 2 ⅜ inches apart

• No drop-down sides

• Crib mattress at an appropriate height setting