How long do professors in US Colleges and Universities have to post grades during a course after the ends?

There's no single, universally mandated timeframe for professors to post grades in US colleges and universities after a course ends. The deadline is usually set by the individual institution (the university or college itself), the department within that institution, or even the individual instructor (though this is less common and generally subject to departmental guidelines).

These deadlines vary widely, ranging from a few days to several weeks after the course's official end date. Some institutions might have strict deadlines tied to registrar's office processes for transcript generation. Others may be more flexible.

To find out the specific deadline for a particular course, a student should check their syllabus, the department's website, or contact the instructor or the university's registrar's office directly.