Suppose I'm in charge of getting a three hundred page book published. I'll do all reasonable things to get it proofread, but still there is a chance that some errors will persist.

Now the book goes to the bookstores and readers start reporting errors. I'd like to know whether the rate of errors is "acceptable" or if I haven't really done my job.

Is there any standard, or any informal rule, for how many errors are "acceptable"?

  • 4
    @Standback: I've seen that question, but it's not a dupe of this one. That question asks about hiring one proofreader and the expectations from that process. This question asks about the ultimate result - no matter how many proofreaders. Could you please reopen it?
    – sharptooth
    Commented Dec 4, 2012 at 10:40
  • 4
    OK, Google turned up references to multiple proofreaders, so I'm reopening.
    – Standback
    Commented Dec 4, 2012 at 13:47
  • 3
    @JohnSmithers: You can see I was concerned with the similarity as well. But one question is basically asking what a proofreader's contract covers, while the other is asking what responsibility the editor has. I'm persuaded there's a difference here - though, honestly, I don't see answers to either beyond "here's a little-known metric" and "there's nothing precise, it just shouldn't feel like too many errors".
    – Standback
    Commented Dec 5, 2012 at 22:37
  • 2
    One fundamental question: How in the world are you going to determine how many errors remained, after your book went through a couple proofreaders??!
    – SF.
    Commented Feb 22, 2017 at 13:18
  • 2
    @sharptooth: If you've found such a reader, you might want to start looking for unicorns in your garden. They are less legendary a creature.
    – SF.
    Commented Apr 13, 2017 at 23:42

14 Answers 14


Some errors will always remain, no matter how many proofreaders go through the manuscript. I've yet to see an error-free book.

Some readers will always be critical. If it's not the proofreading, it's the editing. If it's not that, it's the fact-checking, and so on. Just steel yourself for the critics, and hope they find happier ways to amuse themselves, soon.

I'm not sure there's any "error rate" to share with you. A single-letter error -- leaving an "s" off a plural, for example -- isn't the same as using an entirely incorrect word (accept, except), and some errors are more glaring than others.

A book that's been hastily proofread by just one proofreader may display 1 typo per 1,000 words. In my opinion, that's too many, but it's not unusual among published books I've been sent to read and review. I'm more comfortable with 3 typos (single-letter errors or two letters, transposed) per 10,000 words.

  • 2
    True. Most readers who are also writers, can't take off their critique hat long enough to review a book properly. They will always find a fault, and usually end the review with "...a good editor could have fixed that". Good editor meaning themselves, of course. So yeah, can't avoid the "critics" Commented Dec 5, 2012 at 15:40
  • 1
    One of my books, after considerable editing, had an average of one error per page. That's a lot. But nearly all of them involved exchanging period for comma, or vice-versa. Computer screens often can't show much difference. Neither can many office printers. But they were easy to discern in the proof copy, printed to much higher resolution. Corrected, re-proofed. Still a few errors in the novel, discovered at leisure. Those involved incorrect singular/plural or verb tense.
    – user23046
    Commented Apr 18, 2017 at 20:08

No errors are acceptable, period.

If I were to write out three paragraphs of text on here, I would check each paragraph for errors until I was satisfied they were all correct before I clicked the 'Post Your Answer' button. If I found errors, I would not be satisfied with what I'd written until it was correct.

Why would a 400 page book be any different? As far as I'm concerned it isn't.

However, living in the real world and being the pragmatists we are sometimes compromises need (and have) to be made.

How much money are you prepared to spend on proof reading those 400 pages over and over and over and over again to ensure there isn't one single error left? Because you can do that if that's what you're prepared to do. However, for most people, business people, writers, publishers etc that simply isn't financially viable.

You have to draw a line somewhere and accept that given your budget for publishing that 400 page book you cannot spend all your money on proofreading and for the project to be financially viable you will have to accept that some errors will slip through the net.

So what it really comes down to is a cost v error acceptability rate. What that rate will be will almost always come down to how much money you're prepared to spend on it and the quality of the people you spend it on.

You're 'worried you haven't done your job', as far as I'm concerned just getting the 400 page book published means you've 'done your job'! If it contains any errors, log them and correct them on the next reprint!

  • 1
    I guess a few errors always pass, that's unavoidable, no matter how good you are. Specially because as a writer you read the same page over and over and sometimes your brain just can't detect small mistakes anymore. In my opinion and experience, at some point, you need somebody else to help with the proofing. I guess you are being too much black and white here. Commented Jun 11, 2013 at 18:51
  • Even books from major authors, published by major publishing houses, often have errors. It may well be that if a book is guaranteed to sell (then be forgotten in two months, when the movie comes out) there is little incentive to proofread. I have also seen page after page of whoppers (not just typos!) in a college textbook, from one of the largest American publishers of such things.
    – user23046
    Commented Apr 18, 2017 at 20:03
  • I think you need a comma in "However, living in the real world and being the pragmatists we are sometimes compromises need (and have) to be made." :p
    – Stuart F
    Commented Nov 7, 2023 at 16:46

With self publishing these days, errors are inevitable. I wouldn't mind too much to 3 or 4 errors as long as the flow is there. Anyway that is me. I am an author as well but even after reading my books over and over many times, it was disappointing to find errors.

  • 1
    Three or four errors per page acceptable? (For the OP's 300 pages, that's a thousand errors.) That's a lot in my mind.
    – user
    Commented Oct 21, 2015 at 13:31
  • If I saw that, I'd complain about the culture of blogging and text messages corrupting the print business!
    – JDługosz
    Commented Oct 21, 2015 at 18:27
  • this is true, sans editor, mistakes are inevitable.
    – Tapper7
    Commented Feb 17, 2016 at 13:09

The most important thing about "acceptability" of errors is that they don't disrupt the reader. That means that some errors weigh heavier than others, even if you have the same number of typos.

Consider, for example, the fact that most Americans these days get "you're" vs. "your" drilled into their head during school. It creates a bias towards the focus on these mistakes, and so I would guess that a lot more readers would notice the misuse in a sentence a lot quicker than the intentional singular use of the word 'head' earlier in this paragraph. You should be cautious of these.

Next, there's the pacing of the book itself. If you're in the middle of a gripping action sequence, a light error will probably be completely skipped over by many readers even if they see it, because they're so engaged with the scene, but a hard error will probably stop them in their tracks and make them pause and re-read the whole sentence. This disrupts the flow of your story and can really detract from the strength of a writer.

Consider the frequency of the error that occurs. There was one book that had a silly typo -- let's say it was allusion instead of illusion (I'm going to remember what it is later). The first time I noticed it, I gave a soft snort and continued reading, my opinion of the book generally unaltered. Typos happen. However, the author persisted to use the same word, maybe once every two chapters. Every single time, they used the wrong word. It drove me absolutely bonkers, because there was no particular reason for them to be using the word all the time in the first place. I don't remember what book it was, and I actually enjoyed both the characters and the plot, but every time I open it up and get to that first typo I groan. This book again.

My general opinion is that as long as your typos are 'soft' and your book is 300 pages long, a reader can probably choose to ignore them if you have fewer than 30. If the plot/characters aren't good, they probably won't bother. On the other hand, if you only have 5 errors in a 300 page book, even though the reader may notice them, they won't remember them when thinking about the book as a whole.

The hard errors probably will be remembered regardless, but if you only have one or two (and your book is otherwise well-written), your readers will probably choose to ignore them. Just make sure they don't take place during critical scenes.


Errors abound in everything from Stephen King novels to The LA Times. Daily newpapers get sort-of a pass from me, because they are on tight deadlines, but still it drives me nuts seeing errors in the 'A' section every time I read it. With books, there should be -

  1. more editors
  2. more time
  3. multiple editions

This makes prose, style, spelling, grammatical and clarity-type mistakes harder for me to swallow. Maybe it's because I have some form of OCD and I catch errors w/o looking for them.

to answer - the number of acceptable mistakes is zero. Pro musicians are expected to sight-read at a 100 percent proficiency. That means; it has to be perfect the first time else--> get fired. In Process Improvement we identify action(s) that drag "on-time-delivery" (usually of widgets), We call it a finished-project once we deliver 'dem widgets on-time & error-free over 98.5 percent of the time. Only in baseball is it ok for pros to accomplish their main function less than 30 percent of the time.

  • Patently not true for Pro Musicians. Commented Jul 12, 2022 at 22:33

Whether such a threshold exists or not is irrelevant, since you can never know whether you have met it or not.

If you detected an error, you would fix it, so the number of known errors is always zero. The number of unknown errors is unknown because you can't count unknowns. Therefore there is no way to know if you have an error rate below any given threshold.

Of course, over time, readers may discover errors in your work. There is no way to know if any one reader discovers all the errors, or if all the readers collectively have discovered all the errors, since a) they don't report them systematically, and b) you can never know how many undiscovered errors remain.

This means that you can know if a work has passed the acceptable error threshold for an individual reader if they write to you and say, "I discovered 10 errors in the first 73 pages so I stopped reading." But that does not mean any other reader will ever notice all those errors, or that if they do it will provoke them to stop reading and write you a nasty letter.

Finally, even if no reader has found enough errors to stop them reading yet, that is no proof that the next reader may not be more sharp eyed or more irritable than than all the others may not find enough errors to trigger their refusal to read on.

A much better measurement might be this: the rate of error discovery. That is, how many errors do you find and fix in each pass through your work. Presumably this number will decline each time through. How many errors do other readers discover each time they read it? You can then set an acceptable error discovery rate per pass for a certain number of readers as a measurable quality metric.

Of course, the Web changes all of this, because now errors can be fixed after publication, something that even extends to published ebooks which can, like software, download periodic updates.


Single digits total, and they'd better all be single-character typos, not bad spelling out of ignorance, mixed up words or mangled sentence structure. And never appear in chapter titles, on the title page, or on the cover. Any more than that and the proofreading wasn't sufficient. (Maybe the proofreader wasn't very good, maybe it needed one more round because there was a lot to begin with, and maybe someone should have looked at it after typesetting too - dunno about English but in my language, automated word splitting is a notorious offender.)


I have to edit my own books frequently. But I publish ebooks -- which allows you to update the ebook file if you find errors.

With printed stuff, you really need a second pair of eyes to find typos. The risks are too great -- especially if you are paying for advance copies.

On the other hand, print-on-demand services (like Createspace) do allow you to update the manuscript after publication.

If you are not confident of your quality control process, you might want to look into a distribution method which allows you to update the manuscript after publication date.

Frankly I worry more about typos than about inconsistent punctuation because one typo lowers a reader's confidence about the book's quality.

Also, technical books and manuals have to undergo additional vetting from an editor who does technical review-- because a mistake can result in bad information. At the same time, all technical publishers know that errata will occur and often have a web page on the company site listing issues and corrections.

A typical developer buys a programming book with the near certainty that it will usually contain technical errors. But they don't sweat it as much because it will help them with general concepts, and generally they can spot the error -- even though it may not run properly. The typical developer wouldn't mind an occasional misspelled word as long as the code works or the technical knowledge is basically right. Also, many IT books are out-of-date by the time they are published, making it all the more important to check for errata.


Error Rate per Page Response

total errors/total pages is one way or total errors/ total pages*100 (Error Rate) limits should be under 1%

I prefer Defects per Million (DPM) DPM should be under 50 Total Error/(total pages * attributes per page)*1,000,000. Attributes per page is a number predetermined for all calculation. We use a standard 300 attributes per page.

I can standardize this error across all efforts and I classify individual error codes 1-55 to pareto chart which area my defects occur most often. i.e. typo, grammar, style, formatting etc.


Aim for as few errors as possible. Editors and publishers may overlook the very occasional error, but not if they see five a page. Get your manuscript proofread as much as possible before you send it.


There should be no errors. I think garnering justification or seeking comfort because they have been found is no substitute for learning from them. Any mistake is jarring for the reader and chastening for the author. We are often word blind, it's true, but we should not at any point regard overlooking mistakes as acceptable, even if there are sloppy readers, who won't notice them.

  • Minor grammar mistakes (the ones likely to get through the proofreaders) shouldn't be enough to justify a new edition of the book.
    – FFN
    Commented Dec 10, 2017 at 18:09

I don't think the issue is mistakes. The issue is acceptability. Perfect is the enemy of good because perfection simply isn't possible. The goal is to write the book. No matter how many proofreads you do, mistakes will happen because language itself changes. Grammar and spelling rules alter every few centuries, so if your book survives it won't be your book because the content has changed due to new rules of how to write. All you can do is try, everything else is a gamble.


From what I've observed in the other answers, there are generally two opinions: either all errors are unacceptable, or some minor ones are acceptable. (Have you noticed a potential run-on sentence just now? Because "some minor errors are acceptable" is an independent clause next to an independent clause, I would've caused a run-on sentence had I not separated both clauses thereof with a comma prior to the conjunction "or." This is similar to what another user, Scott, failed to notice when he wrote, "All you can do is try, everything else is a gamble" without a conjunction, period, or anything to properly separate these two independent clauses.)

But despite me being an analytic philosopher, whose occupation literally implies truths that are contained within definitions, I'll have to agree that grammatical errors are almost inevitable from a practical standpoint; almost no books ever published are error-free, and depending on one's knowledge of the language used, more errors will appear.

I noticed that the users who were harsher on errors committed ones in their own responses. For instance, spiceyokooko, an interesting choice for a username, wrote in his or her second paragraph, "I would check each paragraph for errors until I was satisfied they were all correct" before submitting his or her answer. What I found intriguing is the missing punctuation by the et cetera abbreviation, etc., which should always end in a period; had it been a well-known acronym (as opposed to an abbreviation), then he or she would not have needed to use any periods with respect to it.

Another error occurred when spiceyokooko didn't use a period following the abbreviated versus (i.e., v.) and another when "400 page book" was written without a hyphen; the latter error was repeated four times! (Someone hasn't been proofreading!) So, what do these tell us? In a matter of 279 words, spiceyokooko made at least six grammatical errors (seven, if we count the missing Oxford or serial comma near the end of his or her response) and probably more if I were less impatient in finishing this response and more patient in reading his or hers for additional errors.

The point of the above example isn't to denigrate anyone, but it's to show that in almost a standard book page's worth of text, even someone who appears to be well-versed in English and committed to reviewing just 279 words will make several blunders, ones that are pretty easy to spot (i.e., a missing hyphen, missing periods following abbreviations, etc.). It's to say that—to answer your question, sharptooth—the average number of mistakes in a published book could be somewhere near five mistakes per page, if someone is a decent writer; yes, five mistakes per page would be exceptional. The reason why these mistakes aren't being found is that even copyeditors, who could cost between .2 and .4 cents per word or 2.5 to 5 dollars per page, only know a fraction of all the grammatical rules, and of those that copyeditors do know, their understanding of them isn't 100%. For example, I haven't met a single English teacher who properly understood the definite article, despite it being by far the most used word in the English language! How did this happen? How did every philosopher I have ever known likewise fail to understand, by far, the most used word in the English language? This is unfortunately the dirty truth of an author's job; one would have to be a hypocrite to tell you that all mistakes are unacceptable while committing mistakes himself. This is why, when I talk about grammatical correctness, I review and review what I write so that I am setting an example for others. So far, I reviewed my response five times before hitting submit, and I submit that there might be an error somewhere, but perhaps the error would be found by someone who knows a less accessible rule of grammar than the ordinary English reader.

If someone had a full understanding of grammar, there would no doubt be the occasional contradiction within grammar itself, but the best advice I can give is that if you want the safest bet of what passes as "acceptable," despite standards that change from publisher to publisher, just make no grammatical mistakes at all; stick to safe sentences that you know you can write well, avoid staying up late at night, upsetting social situations with friends or work colleagues, avoid drinking, make sure to review everything you write, and then print and review your work. Repeat this process sentence by sentence until you can recite your book with your eyes closed. While it's certainly time-expensive and emotionally expensive, it's what separates mediocre authors (sometimes they are erroneously hailed as "greats" within our generation) from truly magnificent and legendary ones (i.e., the ones that are born once a century). The alternative is to keep errors to about five or fewer per page, and, if we're being honest with ourselves, you're doing fine by authors' standards.

Thanks for reading my response. (I respond to people.)


If it's okay with Stephen King, it's okay with me. I have proofread my book no less than ten times and I still find errors. I'm not perfect and neither is anyone else. I feel confident that most readers don't judge a book by its typos.

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