apa abstract length

Per section 2.9 of the APA manual, an abstract is a brief summary of the paper and should be no more than 250 words. Most scholarly journals require an abstract, but abstracts are usually not required for student papers. If you are not sure, please ask your instructor if an abstract is required for your paper.
If one is required, the abstract is placed on its own page after the title page, so it will be on page 2. The APA Style Blog has two sample papers for review. The sample professional paper includes an abstract. The sample student paper does not include one since this is not usually required.

The purpose of an abstract is to provide a reader with a short summary of a your written work or research paper. Generally, it is one paragraph ranging from 150 to 250 words . A well written abstract should be:
Some writing assignment instructions may indicate that an abstract is required, although a majority of student writing assignments do not require one. Consult with your instructor to clarify assignment requirements if you are uncertain.

The principal presented awards to three fourths of the student body.

(This is a new rule in APA 7. APA 6 recommended using numerals in the abstract.)

References:

http://rasmussen.libanswers.com/faq/32740
http://academicguides.waldenu.edu/writingcenter/apa/other/numbers
http://askus.baker.edu/faq/218266