There is no set length of time for an arraignment hearing. As an initial matter, it is important to understand that even if your hearing is scheduled for a specific time, court calendars are often incredibly busy. It isn’t unusual for a hearing that is set for 9:15 a.m. to start at 10:00 a.m. or later.
The overall length of an arraignment hearing will depend on a number of factors, such as whether you plead guilty, no contest, or not guilty, and whether your attorney makes an argument as to bail. If there are other legal issues in your case, such as the need for a probable cause hearing or an issue with a different matter, like a restraining order, then it may take additional time to resolve. Generally, you should expect to spend more time waiting than time spent before the judge, which may be a matter of minutes, unless there are lengthy legal arguments to be made.