GPA - how to understand?

<p>Hi, I am an international high school student thinking about applying to some universities in the U.S. But my problem is that I have different grading system (1-6) and I don't know how to calculate my GPA.<br>
But even the biggest problem, which rankles me, is how to understand "GPA" which is required by universities. How is it counted? Because I don't understand whether my grades from the last semester before application are important or all grades from 4 years of high school...</p>

<p>Unless a college asks you to report your GPA on a 4.0 scale, which is very unlikely, use the scale provided by your school.</p>

<p>Colleges vary as to which years’ grades are counted/considered important. Some (e.g. University of California) do not count 9th grade grades. Others are looking for upward progressions or maintaining a high level. Top private universities looks at GPA as one part of the application process, together with test scores, EC’s, essays, and recommendations.</p>

<p>Mainly I’m thinking about these top private universities as you wrote. I know that GPA ia only a part of the application process, but GPA from which years of high school is required by Harvard/Princeton/Yale etc? I can’t find any information on their websites. And is this GPA the sum of GPAs from 2/3/4 years of high school or what?</p>