The Reading-Level Checker Prompt: Write Cold Emails at a Grade 3-5 Level

Why simple emails win

Boomerang, an email tool, studied the replies to emails sent by its users, from a pool of over 40 million emails where people asked for a reminder if nobody replied. As Fortune reported, emails written at a 3rd grade reading level got a 53% response rate. At a college reading level, only 39% got answers.

In Boomerang's own write-up, 3rd grade level was the best. It gave a 36% lift over college level and a 17% higher response rate than high school level. Same offer, said simpler.

One honest note: this study looked at everyday emails, not only cold emails, and it's from 2016. But cold email data points the same way. The Gong x 30 Minutes to President's Club report on 85M+ cold emails found replies were highest for emails of 51 to 100 words and 3 to 4 sentences.

Why it works

• People read cold emails on their phone, fast, between other things.
• Short words and short sentences can be understood in one quick look.
• Hard words make the reader work. When reading is work, people skip it.
• Simple doesn't mean dumb. It means the reader gets your point in seconds.

What "reading level" means

Most checkers use the Flesch-Kincaid Grade Level. It only looks at two things: how long your sentences are, and how many syllables your words have. Microsoft's formula is: 0.39 × (average words per sentence) + 11.8 × (average syllables per word) − 15.59.

So the score goes down when you use shorter sentences and shorter words. That's it. A grade 3 score means a typical 3rd grader could follow it. A common rule for cold email is to aim for grade 3 to 5.

The 4 rules

1. Short words

2. Short sentences

If a sentence has a comma and an "and", it's probably two sentences. Split it. Most lines in a good cold email are under 12 words.

3. One idea per line

Give each idea its own line, with space around it. One line for why you're writing. One for the problem. One for what you do. One for the ask. On a phone, this looks easy to read before they even start.

4. One clear ask

This is the part the reel warns about: it won't work unless you keep one clear ask. A simple email with three questions at the end still confuses people. End with one easy question they can answer in a word.

Worked example: before and after

Before (55 words, 3 long sentences, about grade 17 by our Flesch-Kincaid count):

I wanted to reach out because I noticed your organization is currently experiencing significant growth in the commercial construction sector. Our comprehensive platform facilitates streamlined project management workflows, enabling teams to substantially reduce administrative overhead and accelerate delivery timelines. Would you be available for a thirty-minute discovery call next week to explore potential synergies?

After (39 words, 6 short sentences, under grade 4 by the same count):

Saw you just opened a second office in Austin. Congrats. More jobs means more paperwork. Most teams lose hours a week to it. We help builders cut that time down. Want me to send how one firm did it?

Same offer. The second one says what they noticed, names the problem, says what they do and asks one small question. Different checkers count syllables a little differently, so your tool may show slightly different scores.

How to check your email for free

1. Paste your email into a free checker like Hemingway Editor. It shows the grade and highlights hard sentences.
2. Or use Microsoft Word or Outlook: they can show readability statistics after a spelling check.
3. Fix the highlighted sentences first: split them, then swap long words for short ones.
4. Check again. Aim for grade 3 to 5.
5. Read it out loud. If you run out of breath, the sentence is too long.

The reading-level checker prompt

You are an editor for cold emails. Here is my email:
[paste email]

1. Estimate the Flesch-Kincaid grade level. Show the word count, sentence count and average words per sentence.
2. List every sentence over 12 words and every word with 3+ syllables that has a simpler swap.
3. Rewrite the email so it scores grade 3 to 5. Rules:
   - Short words, short sentences, one idea per line
   - Under 80 words
   - Keep every fact, number and name exactly as I wrote it. Don't add new claims.
   - Keep industry words my reader uses every day
   - End with ONE clear question they can answer in a word
4. Give the new word count and estimated grade.

Note: your grade is an estimate. I'll confirm it in a free readability checker.

Common mistakes

Links and tools

Quick answers

Won't a 3rd grade email sound childish to a CEO?

No. Simple words aren't childish, baby talk is. Executives read fast and love emails they understand in seconds. Keep the facts sharp and the words plain.

Which readability checker should I use?

Any one is fine. Hemingway Editor is free in the browser, and Word and Outlook have a built-in readability check. Use the same one every time so your scores are comparable.

Is grade 3 to 5 a hard rule?

No, it's a common rule. Boomerang's best result was at grade 3. If your email is clear and short at grade 6, that's fine.

Should I remove technical terms my buyer uses?

No. If your reader uses a word every day, keep it. Just keep everything around it simple.