It is a wooden full-size or mini crib that we can later convert into different bed options. Except for a daybed, you need a conversion kit for all transformations. For instance, to convert the crib into a toddler bed, you need a toddler guard rail. So, what is a convertible baby crib? In short, this is a crib designed to go through different phases of your child’s life. It grows with your child and can be even a lifetime crib/bed.