According to WebMD, many children begin toilet training between 22 to 30 months of age, but it is best to begin when the child is ready. Children are typically ready when they can control their bladder and bowel muscles.
One sign that a child may be ready to begin toilet training is when the child uses the bathroom about the same time every day. Children who do not have a bowel movement at night may also be ready. Children with basic motor skills such as speaking, walking and climbing are generally ready.
When a child goes to the bathroom when he needs to and can position himself on the toilet with little assistance, he is considered toilet trained.