Just like babies, crib mattresses come in different sizes. Looking at a mattress, you wouldn’t know, so we’re here to answer the question “Are all crib mattresses the same size?”. We’ll also explain why crib mattress size matters!

How Big is a Crib Mattress?

There are so many styles of cribs on the market - modern, traditional, convertible, designer, bare-bones, take your pick! No matter the design, any crib manufactured and sold in North America, must be built to fit a full size crib mattress. So, what are the dimensions of a crib mattress and how long is a crib mattress? All North American crib mattresses must measure between 51 ⅝ to 53 inches in length and 27 ¼ to 28 inches in width (thickness can range from 4 to 6 inches).

Why the Variance in Size?

There are three main reasons: 

  1. Fit: If you can place more than two fingers between the mattress and the crib, the mattress is too small. Some mattress brands use smaller dimensions to cut costs. Nook’s priority is safety, so we make all of our mattresses to the larger variance of US standards.
  2. Firmness: Foam that’s too soft or bouncy inner springs can contribute to a mattress with too much “give”, leaving gaps around the edges. This poses a safety hazard if tiny hands or feet, or even worse, baby’s face, gets caught between the mattress and crib rails. Nook’s dual-sided crib mattresses are ultra-firm on one side for infants, and firm on the other side for toddlers - safe for developing spines, and no safety hazards!
  3. Materials: What your crib mattress is made of plays a major part when it comes to how a mattress will fit in the base of the crib, like the aforementioned soft foam or inner springs. Depending on which crib mattress you choose, Nook uses organic coconut coir, rubber natural latex, upcycled cotton denim, or non-toxic CertiPUR®-US foam to achieve a firm, safe, and breathable crib mattress.

 

What Size is a Nook Crib Mattress?

All Nook crib mattresses are made to the larger variance of standard crib mattress dimensions (53 x 28 x 4 inches) which allows for a nice, snug and safe fit in the crib. Pro tip: a thicker mattress doesn’t necessarily mean more comfortable or safer. What’s most important is the materials, as we explained above, to provide a firm, breathable and safe crib mattress. Another feature of Nook mattresses is the square, not rounded, corners. This eliminates any gaps at the crib base. Whatever style you choose for your nursery furniture, you know that using a Nook mattress will give your baby a safe sleep environment, both in fit and breathability!

Bottom line: Make sure your crib mattress is at least 52x28x4 inches and it will fit in all modern-day cribs. This reduces the risk of any gaps between the mattress and the crib edge that could pose a potential danger to your sleeping baby.