There are some milestones you look forward to eagerly; your baby’s first laugh, the first time your baby says mama or dada, their first steps…and lowering their crib mattress?
All right, so lowering the crib mattress may not be on parents’ top 10 list of exciting milestones but it is an important safety milestone in your baby’s life!
One essential safety feature of cribs is the ability to move the mattress to different height levels. As your baby gets bigger, taller and more mobile, lowering your crib mattress will keep them safely confined inside their crib.
Even though we know about the possibility of lowering crib mattresses, it is perplexing to many parents to know when you are supposed to do it. Worry no longer, we are here to walk you through the ups and downs (wink) of when to lower your crib. Read on for all of the tips and tricks you’ll need to keep your growing baby safe in their bed.
Note: this blog post probably contains affiliate links, which means we may receive small commissions from purchases made through links in this post (at NO extra cost to you). You can read our full disclosure for more information.

Why Getting the Right Mattress Height Is Important
If the goal is to keep baby from tumbling out of the crib, why don’t we just start with the mattress at the lowest setting? Well first of all, it is easier for parents! Keeping your baby at the highest mattress setting when they are newborn-a few months old makes it easier for parents to lift baby in or out of the crib (especially if you had a c-section!).
As your baby gets bigger, they will be able to sit up, pull up and eventually stand up in their crib. Getting the right mattress height is important so your baby won’t tumble, crawl or roll out of their crib.
Obviously keeping your baby from falling out of the crib is more important than making it easier for parents/grandparents to lie them down. The trick is to move the bed down incrementally to make it as easy as possible for the parents while still keeping your baby safe.
When Should You Lower Your Crib’s Mattress Height?
Let’s dive into the nitty gritty of lowering your crib’s mattress height. There are age guidelines as well as signs you can look for in your baby that will help keep them safe. Here are some general guidelines (read on to get more in-depth information.)
Crib Height Setting | Age | Signs it is time to change mattress height |
Highest Level Crib Setting | Newborn to 5 months old | Rolling independently, pushing up |
Middle Level Crib Setting | 5 months old to 8 months old | Sitting up independently, pushing into crawling position |
Lower Level Crib Setting | 9 months to 18 months old | Standing, climbing |
Floor Crib Setting (if available on your crib model) | 18 months to 24 months old | Climbing out of the crib, not wanting to go to bed, taller than 35” |
Transition to Toddler Bed | 24 months+ |
PRO TIP: It is safest to lower the mattress height earlier than you absolutely need to. If you are nervous, you can always use a lower setting from the get go! If you or your partner (or grandparents) are on the shorter side, purchase a step stool like this to keep next to the crib that will make it much easier to lower baby down… and be super careful, otherwise this might happen:
When to Use the Highest Level Mattress Height
Birth – around 5 months
You can keep your crib mattress at the highest setting until your baby is around five months old.
Watch for these milestones that make it dangerous for your baby to have their mattress at the highest level:
- Rolling over independently
- Pushing up: lifting their upper body off the mattress
Remember that all babies reach milestones differently. You might need to lower your baby’s crib mattress earlier than five months. Your baby might be rolling around at 3 months old, at which point you should move the mattress down a level. However, somewhere around five months most babies will be rolling over and pushing up and need their crib mattress lowered.
When to Use the Middle Level
5 months old – 8 months old
The middle setting works well for babies between 5-8 months old. Babies at this age are still very dependent on mom and dad to get them from point a to point b.
Watch for these milestones that mean it is time to move your baby’s crib mattress to the lower level setting.
- Sitting up independently
- Pushing up into crawling position
No worries if your child hasn’t reached these gross motor skills at 8 months old, you can keep your crib mattress setting right where it’s at for longer. However, once your baby is sitting up and getting close to crawling, it is safest to move the crib mattress to the lower level setting.
When to Use the Lower Level
9 months – 18 months old
At this point, your baby’s mobility will really take off! Between 9 and 18 months, they will start crawling, pulling up, climbing, walking and (believe it or not!) running! To keep your baby from unsafely exiting their crib when you are out of the room, it is now time to move the crib height to the lower level.
Watch for these milestones that mean it is time to move your baby’s crib mattress to the lower level setting:
- Standing up independently
- Climbing
When to Use the Floor
The design of some cribs allows for an additional floor level setting when you place the mattress directly on the floor inside the crib. This height makes it nearly impossible (or at the very least difficult) for most babies to climb out of their crib.
You should only put the crib mattress on the floor if your crib has been manufactured to have this as an option. Refer to your crib instruction manual and/or call the manufacturer to confirm this. Do NOT put the mattress on the floor if there is any gap between the mattress and the bottom of the crib as this would be extremely dangerous choking/injury hazard.

When Should you Transition to A Toddler Bed?
24 months+
The transition to a toddler bed from a crib can be a controversial subject. Some people want to keep their baby in a crib as long as possible. If your baby is sleeping well and isn’t in danger of climbing and falling out of the crib, you can definitely keep them in the crib longer than 24 months.
However, if you were blessed with a monkey baby, need the crib for a younger sibling, or just think those toddler beds are so doggone cute, you can transition to a toddler bed somewhere around two years old.
Watch for these milestones that mean it might be time to move your baby to a toddler bed:
- Your toddler can and will climb out of the crib
- Your child’s height is taller than 35”
- Trouble getting your toddler to sleep in their crib
There are so many adorable (and useful!) types of toddler beds available to choose from. Some of our favorites are:
A floor bed: A floor bed has the mattress directly on the floor, which makes it easier for toddlers to get in and out (a blessing, and also a curse). This floor bed has a frame shaped like a house with picket fences and would be a sweet big boy/big girl bed!
A classic toddler bed: These are lower down to the ground and the perfect size for a toddler. You will eventually need to size up, but a toddler bed is less intimidating for a little one to sleep in than a giant grown-up bed.
A normal sized bed with a bed rail: If you go this route, I might recommend sizing up to a queen! This makes it easier for mom or dad if your little one wants someone to lay next to them after a bad dream or when they are feeling under the weather. Sleep is precious, y’all!
The Final Word
Knowing when to lower a crib mattress might not be a conversation starter at a party, but it is important! Being aware of the age ranges and signs that indicate it’s time to lower your baby’s crib mattress will give parents peace of mind and keep your baby safe.
Remember, if you are a worrier, you can begin with the crib mattress at its lowest position. It is safe to do this, it just makes it awkward and sometimes difficult for parents to lower a sleeping baby onto the mattress. You can add a step stool to make it easier for everyone!
We hope this guide has cleared up any confusion about when to lower your crib’s mattress. Pay attention to your child and his/her abilities. All babies are different and will reach milestones at different times. Be confident in your ability to know your own child’s needs and to keep them safe. You’ve got this!