Estimate time to edit a document.
Editing rates vary by more than six times depending on depth, and that is the variable that decides the estimate. Professional benchmarks are roughly 2500 words an hour for proofreading, 1200 for copy editing, 700 for line editing and 400 for developmental work where you are reshaping argument rather than sentences. Draft quality scales all of these — a rough draft slows any level of edit by around 40 percent. Later passes are much faster than the first because most problems have already been fixed, which is why the calculator applies a decay of about 30 percent per pass rather than multiplying the first-pass figure.
Effective rate
Words per hour = depth rate / quality factor
Multiple passes
Each subsequent pass takes about 70% of the previous one
Because it works on structure rather than text. A developmental editor has to hold the whole argument in mind, judge whether each section earns its place, and identify what is missing — which requires reading, thinking and re-reading rather than moving linearly through sentences.
Yes, on a well-executed edit. The first pass finds the majority of problems; the second is largely confirming fixes and catching what the first missed. If your second pass takes as long as the first, the first pass was probably too shallow or the draft needs structural work instead.