When a child grows big enough to move on from the crib, the next step is often a toddler bed. A toddler bed mattress is typically the same size as a crib mattress, and sometimes the crib itself converts into a bed or daybed using the original crib mattress. The exact dimensions may vary slightly, but a mattress 27 inches wide and 52 inches long, on average, fits a toddler bed. The bed itself must not have space between the mattress and frame that could prove dangerous to a toddler.
Mattress Safety Concerns
If you have a convertible crib or a crib conversion kit that turns the crib into a toddler bed, the mattress and bed frame already fit nicely together. If you need to buy a new toddler bed, the mattress must fit within the frame snugly -- not all crib or toddler mattresses are the same size, and the mattress may be a couple inches shorter than expected, resulting in an unsafe gap between mattress and frame. Measure the length from the head to foot area within the frame, and purchase a toddler or crib mattress that fits the space with no gaps large enough to trap fingers or arms.