When is a child ready to start toilet training?

What the evidence says

There is no single age when every child is ready to start toilet learning. Instead, doctors say to watch for signs that your child's body and brain are ready, rather than picking a birthday to start on.

According to the Canadian Paediatric Society, your child is probably ready when they show interest in the potty, stay dry in their diaper for a few hours in a row, have somewhat predictable bowel movements, can sit steadily on the toilet, can follow simple instructions, and can tell you when they need to go. Some children show these signs as early as 18 months, but most children start between 2 and 4 years old.

This approach is called child-oriented toilet learning. It was developed because forcing training before a child is ready, or before their body can control the bladder and bowel muscles, tends to make the process take longer and can lead to problems like a child holding in poop or refusing the toilet. The American Academy of Pediatrics agrees, and generally advises against starting before 18 to 24 months.

Age alone is not a perfect test of readiness. One study following toddlers in daycare found that basic skills like sitting steadily, imitating others, and walking without help appear in almost all children regardless of whether they had started training, so these alone do not prove a child is ready. Watching for the specific bladder and bowel signs above is more useful than watching general milestones.

Daytime control usually comes together over a few months. Nighttime dryness often takes much longer, sometimes months or even years after daytime training is done, and that is completely normal. If your child pushes back hard against using the potty, most guidance suggests taking a break for a month or so and trying again later, rather than pushing through a power struggle.