Private schools in Orange County do not share a single admission test requirement: some accept only the ISEE, some accept both the ISEE and the SSAT, and Catholic high schools use a test of their own. Which test a student should take depends first on the requirements of the target schools; when both are accepted, the next step is to compare the two tests themselves.
Levels and grades served
The ISEE is divided into levels by the grade the student is applying for:
| Level | Grade applying for |
|---|---|
| Primary 2 / 3 / 4 | Grades 2, 3, and 4, respectively |
| Lower | Grades 5 to 6 |
| Middle | Grades 7 to 8 |
| Upper | Grades 9 to 12; also used as a high school entrance exam |
The SSAT has three levels: the Elementary Level serves grades 3 to 4, the Middle Level serves grades 5 to 7, and the Upper Level serves grades 8 to 11, covering students in grades 3 to 11 overall.
Note that the two tests draw their boundaries differently. A student applying for grade 7 takes the Middle Level ISEE, while for the SSAT the student is placed in the Middle Level based on current grade. A student applying for grade 9 takes the Upper Level ISEE and also falls in the Upper Level SSAT. At registration, confirm the level against the official guidance rather than inferring it from experience.
What each test covers
The Lower, Middle, and Upper Levels of the ISEE share one structure: Verbal Reasoning, Quantitative Reasoning, Reading Comprehension, and Mathematics Achievement, plus an unscored essay. The Primary levels cover reading and mathematics, and Primary 2 also includes listening comprehension.
The SSAT tests verbal, quantitative, and reading skills, also includes an unscored writing sample, and often ends with an experimental section that is neither scored nor reported.
How many times a student can test
This is where the two tests differ most.
ISEE: one test per testing season. The seasons are fall, winter, and spring/summer, for a maximum of three tests in a school year.
SSAT: the testing year runs from August 1 to July 31 of the following year. For paper-based testing, the Middle and Upper Levels allow up to 6 standard tests plus 1 Flex test, and the Elementary Level allows up to 3 (2 standard and 1 Flex). The SSAT at Home is limited to 1 per testing year. Prometric test centers currently allow 1, and the official page states this will change to 2 this fall.
The practical effect on test preparation: each ISEE attempt carries more weight because opportunities are limited, so a student should test only when ready. The SSAT offers more room for error, and a student can take it once to learn the pacing.
How to decide
Step one: list the requirements of the target schools. This is the only hard constraint. The testing requirements of Orange County private schools are listed in the school directory.
Step two: consider the timeline. When less than one testing season remains before the application deadline, the ISEE limit may mean the student has only one attempt.
Step three: consider the student’s strengths. The two tests differ in question style, and one diagnostic practice test usually reveals more than any comparison article.
Catholic high schools use the HSPT, a separate test; preparation planning is covered in HSPT Prep. Level-by-level ISEE preparation is covered in the ISEE Prep Center.
Sources
- Admission.org (ERB): About the ISEE (accessed September 27, 2026)
- Admission.org (EMA): About the SSAT (accessed September 27, 2026)
- Irvine PSAT/NMSQT in October: How Scores Enter National MeritIUSD gives every junior a free PSAT/NMSQT this October, the only entry to the 2028 National Merit program. Dates by school, score release dates, and selection rules.
- Self-Studying AP: Official Rules and Two Real LimitsCollege Board lets students take most AP Exams without the course, but Irvine families still face two limits: securing a test site and choosing a suitable subject.
- How Many Times Should You Take the SAT?Two to three sittings suits most students, in spring of junior year and fall of senior year. This guide covers the 2026-27 dates, score releases, and superscoring.
- Digital SAT Reading Tips: 8 Strategies That WorkThe Digital SAT Reading and Writing section runs 54 questions in 64 minutes across two adaptive modules. This guide covers the four content domains and eight strategies.
