An AI-drafted email gives itself away in three places: an opening line that carries no information, a closing formula that thanks the reader for their time, and the length. Delete the first sentence, cut the sign-off to three words, and remove a third of what is left. The email stops reading like something that went to forty people. For the sentences in between, the humanizer above rewrites every one of them in one click at 1 credit per 50 words, so a 100-word email costs 2 credits out of the 10 you get free every day, with no account, no login, no card and no email address to verify. Emails run short and the checker scores from 65 words up, so paste a few from the same batch together and score them as one block for a single credit. The batch is the more useful thing to measure anyway.
Vocabulary is the last thing a reader notices. The first is that the email is about the category of the situation rather than the situation. A model asked for a follow-up writes about our recent conversation, because it does not know the conversation was Tuesday's call about the renewal price. Every abstract noun in a work email marks a place where a specific was available and went unused.
The second is length. Someone writing at half past four about a moved meeting sends two lines. A model returns a greeting, three paragraphs and a courteous close, because that is the shape of the thing it was asked for. Length gives it away before anyone reads a sentence.
The third is that the register never moves. The same formality goes to the person at the next desk and to a stranger whose budget you want. Real email tracks the relationship. It gets shorter with people you know, drops the greeting by the fourth message in a thread, and stops capitalising things.
Every edit below makes the email better to receive, which is the point. None of them require writing badly on purpose.
Then read it out loud once. Email that was assembled rather than written is obvious in the mouth before it is obvious on the screen, and the sentence you stumble over is nearly always the one to cut.
A short list of words carries most of the load in work email, because business vocabulary and generated vocabulary overlap almost exactly. The free AI vocabulary checker flags these in your own draft, runs in the browser and costs no credits.
One caution. Swapping each flagged word for a synonym leaves an email with the same shape, the same empty opener and the same missing dates, and a reader will still recognise it. Vocabulary is the cheapest fix, not the one that matters.
The checker gives a 0 to 100 AI score and one of three verdicts: reads as AI-generated, borderline, or reads as human-written. It costs 1 credit per run whatever the length, and it scores text from 65 words up. A one-paragraph email is usually shorter than that.
If you are sending a batch, paste the bodies together. Six near-identical outreach emails come to a few hundred words, clear the floor comfortably and cost a single credit, and the batch is the thing worth measuring anyway, because the shared skeleton is exactly what makes each one read as a form letter. Leave out the greetings and signatures. They are the same in every email anyone sends and they tell you nothing.
For one short email, use the tools that run in the browser instead. The AI writing tells page highlights the flagged phrases in place, and the readability and vocabulary checkers are free and unlimited. None of them touch your credits, and on a short email a list of named phrases is more useful than a number.
One rewrite run takes 12,000 characters, roughly 2,000 words, so an email fits many times over. The floor is the number to know here: the rewriter works from 25 words up, and a 20-word email is under it. A 20-word email is also not the problem.
Cost is 1 credit per 50 words, calculated on each run and rounded up to the next whole credit. A 50-word email is 1 credit, 100 words is 2, 150 words is 3. Ten credits a day is 500 words of rewriting, which is five emails of 100 words.
Because the rounding happens per run, batching saves credits. Three 60-word emails rewritten separately cost 2 credits each, six in total. Pasted into one run, those same 180 words cost 4. Separate them again afterwards.
The rewriter works only from the text you give it, so put the real name, date and figure into the draft before you run it, then read the result once against your facts. An email with no specifics in it comes back as an email with no specifics in it.
Cold outreach. The risk here is not a detector. It is that your first line has already been read this week by the person you sent it to, in somebody else's email, written with the same model. One verifiable detail about their company in the first sentence does more than any rewrite.
Internal email. The risk is not suspicion, it is that colleagues learn your messages can be skimmed. Send 200 words where 40 would do, often enough, and people start reading you diagonally. Then the one that mattered gets skimmed too.
Replies to customers. Match the register of the last message in the thread. If they wrote sounds good, thurs works, then three courteous paragraphs read as machine-drafted whatever the words are. If you are apologising, the apology has to be shorter and plainer than the complaint, because length reads as deflection.
Detection is rarely what costs you in email. What people notice is that the message sounds like the other nine they read this morning, and they answer it last. That is the real cost, and the edits that lower a score are the same edits that fix it: a specific first line, a date, a number, and half the words.
The checker scores from 65 words up, so paste several emails from the same batch together and check them as one block for a single credit. For a one-off, skip the score and use the free in-browser tools instead. The tells page highlights the exact phrases, and the readability and vocabulary checkers are unlimited.
Ten credits a day, at 1 credit per 50 words rounded up on each run. A 100-word email is 2 credits, so five emails of that length. Pasting several short ones into a single run stretches it further, because the rounding is applied once per run rather than once per email.
It rewrites the sentences you give it and works only from what is in them, so write the real client name, the real deadline and the real figure into the draft first. Then read the result once against your facts before you send. Nothing outside your text gets added.
Read the policy that applies to you. Some employers have a written policy, and some regulated roles limit what may be pasted into an outside service, which matters more for confidential content than for a meeting reschedule. Rewriting a draft you were permitted to generate is ordinary editing. Where AI is not permitted, that rule covers the draft however it is edited.
Delete the first sentence and the closing formula, then check that what remains contains a name, a date or a number in the first line. That is three deletions and one addition, and it removes the three things a reader registers first.