1 1/2 I'd say maybe 2. Buy a little potty sit them down on it infront of TV or read to them. Have them sit there for a little. Let them run around with no diaper. Give them tons of praise after using their small potty. My son was so easy to potty train. Trained him in 2 weeks. My daughter is a different story lol

i wouldn’t say there’s a specific time to start, but we started when my daughter started to show signs of readiness.