Potty training starts usually at 18 months. Though you can start making him sit on the potty. There are things that show that a child is ready to be potty trained. Most of these are rarely achieved before age 18 months. How do I know my child is ready to begin toilet training? It depends on several factors, including your child’s age, awareness of toileting-related issues, physical readiness, and communication skills. Beginning toilet training too soon will make the process more frustrating for both you and your child.