A crib mattress is 27×52″, also sometimes referred to as a toddler bed. A mattress of this size provides enough room for infants and growing toddlers.
Crib mattresses can be used in standard-sized cribs, but also in toddler beds (without traditional crib rails).
The image above shows a crib mattress compared to a twin or twin XL mattress.
As you can see, a twin mattress provides 50% more sleeping surface than a crib and a twin XL provides 54% more sleeping surface.
