It should be noted that there are often multiple terms for each level
Early childhood education
Pre-school
Kindergarten (ages 5-6)
Elementary education
Grade 1 (ages 6-7)
Grade 2 (ages 7-8)
Grade 3 (ages 8-9)
Grade 4 (ages 9-10)
Grade 5 (ages 10-11)
Grade 6 (ages 11-12)
Junior High/Middle School
Grade 7 (ages 12-13)
Grade 8 (ages 13-14)
Grade 9 (ages 14-15) note: some school authorities
High School/Senior High
Grade 10 (ages 15-16)
Grade 11 (ages 16-17)
Grade 12 (ages 17-18)
Grade 12 (ages 18-19)
Higher/Post-secondary Education
College: The term college usually refers to a community college or a technical, applied arts, or applied science school. These are post-secondary institutions granting certificates, diplomas, associates degree, and bachelor's degrees.
University: A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is a corporation that provides both undergraduate education and postgraduate education.
Graduate school: A graduate school is a school that awards advanced academic certificates, diplomas and degrees (i.e. master's degree, Ph.D.)