High School
In 2009, the average US national high school GPA was a 3.0, or B average. More recent studies suggest that number could now be as high as 3.38. Average GPA has increased dramatically over the past two decades (in 1990 it was 2.68), but unfortunately the rise isn't necessarily due to smarter students.
You would expect an upward trend in GPA to correspond with higher scores on standardized tests like the SAT and ACT, but in reality those test scores have been slipping. This means the higher GPA average is likely due to grade inflation, not better education.
Apples to Oranges
To make matters worse, the degree of grade inflation varies from school to school, making it difficult to compare the academic achievement of students from different high schools. While GPA still remains an important aspect of any transcript, colleges are increasingly using additional benchmarks like class ranking, course load, and standardized tests.
College
According to a 2006 study, the average college GPA is 3.11, though it varies depending on the major—science and math degrees tend to average below a 3.11, while music and education degrees are higher. Evidence also suggests trending grade inflation at the collegiate level, including a statistic claiming that 62% of grades awarded at Yale University were "A"s.
What does all this mean for you? An above average GPA is an important part of your academic profile, but remember to diversify your coursework with advanced classes if you're capable. Take standardized tests seriously, and don't forget the extracurriculars (especially if you're in high school). Be sure to track your overall performance using our GPA calculator to stay on top of your GPA.