It stands to reason that the rate for editing a text should be less than the rate for translating it from one language to another.

It also stands to reason that the rate for editing a text that requires little editing should be less than that for a text that requires a great deal.

That much is clear. However, determining the precise rate that is appropriate in each case used to be a matter of subjective assessment on my part—which is not an accurate method, and does not reveal to the client how I reached that conclusion.

So for several months, I looked for an objective means of calculating my rate for copy editing, based on an accurate measurement of the amount of editing required for any given text.

Finally, I found it.

There is an excellent site called DiffNow.com which finds and measures the differences between any two texts (up to 512K size—approximately about 13,000 words).

It works very simply: you paste in the “Before” text in one box, the “After” text in the other, then click the button Compare:

Within moments, it finds and marks all the differences between the two, and and classifies these as Added, Deleted, Changed, and something called Changed in Changed (the meaning of which, to be perfectly frank, I’m not quite sure of). On the bottom right, it provides buttons for jumping and examining each change in turn, but more importantly, for me, it provides statistics for the number of changes of each type:

I then feed these figures into a simple spreadsheet, which looks at the total number of words in the original text, the number of changes of each type, then calculates the total number of changes in percentage terms (Total Change %).

I then multiply that number by a fixed number, which I call the Copyediting Coefficient, which currently is 300.*

Why 300? Because that’s the number which, from my experience, when multiplied by the Total Change % figure, yields an editing rate that is correct for a given text, in USD. Thus, for example, a text where the Total Change % was only 10% of the text, the rate would be 10% * 300 = $30 USD. Conversely, a text where the Total Change % is 20% would result in an editing rate of 20% * 300 = $60 USD.

Applying this formula on various sample texts has confirmed that it reflects the degree of editing required in each case. Here are three examples from the period when I conceived of this method:

This, then, is the formula by which I calculate my rate for editing texts (in Hebrew or English). Along with the invoice for each job, I now also provide a screenshot of the calculation and of the DiffNow results, to demonstrate how the rate was calculated.

My clients very much appreciate this rate calculation method, as it provides a measure of transparency that is not available with many other editors.

Incidentally, if a price estimate is required at the start of a job, I edit a sample page or two, then carry out the above calculation on that. In all probability, the final rate may be slightly different, but probably not by much, assuming that the quality of writing is more or less uniform throughout the text.