For most four-year colleges, there is no set grade point average requirement, but a certain level of academic achievement is usually suggested by the admissions office.
Top schools, including the Ivy League and other first-tier universities, typically accept only those students with an "A" average (3.5 to 4.0 or above). This is not to say that other students who apply with lower grades will always be rejected, but the average GPA for an accepted student at Columbia University, for instance, is a 3.8.
Less competitive schools will, according to its selectivity often choose students with a "B" average (2.6 to 3.4) or even lower.
While most community colleges and technical schools are not selective, they usually require at least a 2.0 grade point average. As that average is required just to graduate from most high schools, it should not pose a problem for most students.
How Much Does GPA Matter?
Your academic record is consistently cited by the admissions office as the single most important factor in granting or denying admission. But it's not the only factor. Extracurricular activities, essays, letters of recommendation, athletic or artistic achievements and standardized test scores are also evaluated, so students with weak GPAs should highlight other attributes.
If you had a rough year because of family or personal problems, bring this to the attention of the academic committee. Most universities include a field in applications where you can disclose information that might help a committee view your academic record in context. If you have a legitimate excuse, a school may forgive a semester or more of poor academic achievement.