Cold email length matters less than what you ask for

Short is a sensible default: one clear ask, in two or three short paragraphs, which usually lands somewhere between 50 and 100 words. But the word count itself matters far less than most advice suggests. In the largest cold email dataset we could find, the gap between short and long emails was 0.2 of a percentage point. What you put in the email, and how you lay it out, does more work than how many words it has.

Where the 50 to 125 word rule came from

Search the question and most answers repeat one figure: keep emails between 50 and 125 words. It comes from a February 2016 post on the Boomerang blog. Boomerang looked at more than 40 million emails that its customers had asked to be reminded about if no response came back. Emails of 50 to 125 words all got response rates above 50 percent, a 25 word email got about 44 percent, and response rates drifted down to about 44 percent again by 500 words.

Look at those response rates. Half of all emails getting a reply is normal for messages to colleagues, clients and people you already know. It is nowhere near cold outreach. Hunter makes the same point in its own analysis of cold email word count: the Boomerang data is old and was never about cold email, and no cold campaign at scale gets a 51 percent reply rate. The rule is fine advice for writing to people who expect to hear from you. It was never measured on strangers.

What cold email data actually shows

Hunter exported 34 million emails sent by its users between 2022 and 2024, dropped campaigns with fewer than 50 emails, and removed campaigns with reply rates above 30 percent or below 0.5 percent to keep warm lists and broken campaigns out. Emails of 20 to 39 words had the highest average reply rate, 4.5 percent. Emails under 100 words averaged 3.9 percent and longer ones 3.7 percent. The other buckets, from under 20 words to over 200, mostly sat between 3.4 and 4.1 percent.

Reply.io's research report on cold email copy, based on millions of emails sent through its platform, found something similar on a smaller scale. Emails of 50 to 70 words averaged a 3.3 percent reply rate, against 2.89 percent for 71 to 100 words and 2.82 percent above 100. Templates of 54 words did best of all. Notice that 54 words falls inside Hunter's weakest bucket, 40 to 59 words at 3.4 percent. Two large datasets cannot agree on the best length, which tells you how small the effect is.

The bigger number in Reply.io's report is about shape. Emails written as a single paragraph averaged 2.4 percent. Two paragraphs averaged 4.79 percent and three averaged 4.27 percent. That gap is larger than any word count gap in either study. Both reports are averages from vendors' own users, so they show what tends to go together rather than proving cause, but the direction is consistent: a wall of text does worse than the same idea broken into a few short blocks.

What those numbers mean for one sender

Turn the percentages into emails. Hunter's 0.2 point gap between short and long is one extra reply for every 500 emails you send. Reply.io's gap between 50 to 70 words and over 100 is roughly one extra reply per 200 emails. If you send 50 cold emails a week, you would wait months to notice either difference, and a change of audience or offer would swamp it long before then.

Hunter's own examples make the point better. A 9 word email got a 13 percent reply rate. A 44 word email got 18 percent. A 115 word email got 15 percent. Each was far above average, and each was exactly as long as its message needed to be.

Length is a result of what you need to say. Fix the message and the length usually takes care of itself.

A length check for your next cold email

• Write down the one thing you want the reader to do. If the email asks for two things, cut one.
• Delete anything the reader already knows or does not need in order to say yes: your company history, a list of features, a paragraph about why you are writing.
• Break what is left into two or three short paragraphs. In Reply.io's data, single paragraph emails got the fewest replies.
• Use short sentences and ordinary words. A reader skimming on a phone should get the point in one pass.
• Count the words last, as a check. If you are over 125, look for a second ask hiding in there. If you are under 30, check that a stranger would understand why you are writing.

Judge length by replies, never by opens

Word count barely touches whether an email is opened, because the reader decides from the sender, the subject and the preview line before seeing the rest. Only replies tell you whether the email worked. In Fast Mail Tracker, every campaign shows its open, click and reply rates side by side, and replies are picked up from the Gmail thread itself, matched to the person who sent them. For individual emails, you can switch on an alert for when there is no reply within 72 hours, so a quiet email becomes a prompt to follow up rather than something you forget.

That reply rate is the honest scoreboard for your copy. Just remember the arithmetic above: at small volumes it will tell you whether an email works at all, long before it can tell you whether 60 words beats 90.

Fast Mail Tracker is in early access while Google's security review completes, so places are limited; to see reply rates on your own outreach, use the install button below.