I've worked as a copyeditor and copy chief for both trade and newsstand mags for many years, and I agree with SusanV's comment.
SusanV wrote:
Going back to the original question, I don't know that there is any "standard" or "average" workload; I would think that would have to be dependent on the size of the magazine and the number of copy eds.
I've also found that your boss's level of ineptness/neurosis has a significant impact on your workload. I was copy chief for a business magazine that was extremely successful before the dotcom bubble burst. That magazine's ME had virtually no publishing experience of any kind (I kid you not). To make matters worse, he had OCD to beat the band. As a result, he insisted that
two people proof the
same version of each story
simultaneously. And then he would review both versions and decide which changes he would accept. (Did I also mention that this guy was a control freak who had the habit of re-copyediting your work to his liking? But I digress. . . .)
The magazine I speak of came out monthly and could easily run more than 400 pages an issue, so working well past midnight was not at all unusual. Talk about a nightmare job!
One final comment to the original poster: Judging from the wording of your question, I sincerely and seriously urge you to consider brushing up on your grammatical skills before attempting to determine your worth as a copyeditor.