I have been employed as a proofreader, but most of my work has been done as commentary. As I read and find mistakes, I usually note them to the writer, editor,
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NOTE: these rates are not set in stone and are only an average for this editor. The actual rate applicable to your document will depend on the depth of the edit, the quality of the writing, the topic matter, the proximity of the deadline, the length of the document and several other factors.