Age Classification of Children

1. Infant/Baby: Age 0 - 1

2. Toddler: Age 1 - 3 (Singapore N1: Age 2 - 3)

3. Preschooler/Pre-K/Nursery: Age 3 - 5 (Singapore N2: Age 3 - 4, Singapore N3: Age 4 - 5)

4. Kindergartener: Age 5 - 7 (Singapore K1: Age 5 - 6, Singapore K2: Age 6 - 7, USA Grade 1: Age 6)

5. Children: 7 - 10 (Singapore Primary 1 - 4, USA Grade 2 - 5)

6. Pre-teen: 10 - 12 (Singapore Primary 5 - 6, USA Grade 5 - 6)

7. Teenage: 12 - 18 years old (Singapore Secondary 1 - 4, Singapore Junior College 1 - 2)

References:
http://en.wikipedia.org/wiki/Toddler

http://www.moe.gov.sg/education/preschool/