15 Email Subject Line Statistics (Trends & Best Practices)

Sometimes the hardest part about creating a new email campaign is coming up with a compelling subject line.

What headline would grab your subscriber’s attention the most? Should you use sentence case or title case? Do you need to include an emoji?

I answer all of these questions and more in this post on subject line statistics.

Top Statistics for Email Subject Lines

1. Email subject lines that have 61-70 characters have an average open rate of 43.38%, the highest of all tested character ranges
2. Adding preheader text to marketing emails increases open rates by 13.72% on average
3. Mobile devices have a character limit of 35 for subject lines on average
4. Title-case subject lines have open rates that are 16.33% higher than that of sentence-case subject lines
5. 90.33% of marketing emails do not use personalization in subject lines
6. Including a publication’s name in subject lines increases open rates by 29.35% on average
7. Emails with subject lines that do not include a recipient’s name have an open rate that’s 9.60% higher than emails that do include a recipient’s name in their subject lines
8. The highest-performing word to include in subject lines is “invitation,” which has an average open rate of 56.76%
9. Emails with subject lines that include bracketed text have an open rate of 50.75% on average
10. Mentioning the word “exclusive” in your subject increases open rates by 45.75%
11. Emails with subject lines that do not include an emoji have an open rate of 40.78% on average
12. The beer emoji is the highest-performing emoji to include subject lines, leading to an open rate of 53.57% on average
13. Including the word “video” in your subject line increases open rates by 7 to 13%
14. Around 80% of consumers think it’s unacceptable if your subject line contains spelling and grammatical errors
15. More than 60% of consumers think it’s unacceptable if your email does contain a subject line

General Statistics

1. Email subject lines between 61 and 70 characters have the highest open rate at 43.38%

According to industry benchmarks collected by email marketing service GetResponse, subject lines that have between 61 and 70 characters in total have an average open rate of 43.38%, the highest of all of the character count ranges they tested.

This number comes from a study GetResponse conducted in which they analyzed over 4.4 billion emails sent by the service’s customer base.

Emails with the lowest open rate had subject lines that were between 241 to 250 characters long. These emails had an open rate of 23.50%.

Fortunately, more than 85% of subject lines sent by marketers have fewer than 90 characters, according to SuperOffice.

This data is in line with BuzzStream’s findings as well.

BuzzStream, an outreach platform, analyzed over 6.4 million emails sent through its platform and discovered that emails that had more than 71 characters had the highest open rate at 40.71%.

Their data also revealed that subject lines that have between nine and 13 words have the highest open rate at 40.20%.

Sources:GetResponse, SuperOffice, BuzzStream

2. Including preheader text in your email increases open rates by 13.72%

According to GetResponse’s study, emails that used custom preheader text had an average open rate of 44.67% while emails that didn’t use preheader text had an open rate of 39.28%.

That’s a 13.72% increase for emails that included preheader text.

In case you’re not aware, preheader text is the bit of text that appears after your subject line. It acts as an email preview for most emails.

In fact, if you don’t customize your preheader text, your subscriber’s email client will display the first line of your email as a preview by default.

Your email marketing service should allow you to customize your preheader on an email-by-email basis. Doing so allows you to tease your email a little further.

GetResponse discovered that only 37.53% of the emails they analyzed included a custom preheader. That means 62.47% of marketers don’t bother customizing preheader text.

Source: GetResponse

3. The average character limit for subject lines on mobile devices is 35

BuzzStream also analyzed character limits for emails on different devices.

Here are their findings:

This means that subject lines have a 35-character limit on mobile devices and a 70-character limit on desktop.

Source: BuzzStream

Statistics for Different Subject Line Strategies

4. Email subject lines that use title case lead to an open rate that’s 16.33% higher than subject lines that use sentence case

This is an interesting statistic.

Most email marketers advise using sentence case, claiming it leads to higher open rates. But BuzzStream’s data says otherwise.

After analyzing 6.4 million emails, they found that subject lines that used sentence case led to an average open rate of 35.03% while subject lines that used title case led to an average open rate of 40.75%.

This means emails with subject lines that use title case have an average open rate that’s 16.33% higher than emails with subject lines that used sentence case.

In their study, 78.43% used sentence case, around 22% used title case, and a smaller percentage used all caps.

Source: BuzzStream

5. 90.33% of marketing emails do not contain personalization in the subject line

When GetResponse analyzed over 4.4 billion emails its customer base sent through its platform, they found that a large majority of them did not use personalization in their subject lines.

In fact, 90.33% of the emails they analyzed did not include personalization in their subject lines.

Only 9.67% of the emails GetResponse analyzed were personalized.

Source: GetResponse

6. Including a site’s name in your subject line increases open rates by 29.35%

When BuzzStream analyzed over 6 million outreach emails, they discovered that emails that included a publication’s name in their subject lines had an average open rate of 50.81% while emails that did not include a name had an open rate of 39.28%.

This means that including a publication’s name increases open rates by 29.35% on average.

Source: BuzzStream

7. Excluding a person’s name from your subject line increases open rates by 9.60%

Interestingly, while mentioning a website’s name drastically increases open rates, mentioning a person’s name in your subject line decreases open rates.

In GetResponse’s study, they discovered that emails that mention a person’s name have an average open rate of 35.78% while emails that don’t mention a person’s name have an open rate of 41.87%.

Similarly, in BuzzStream’s study, outreach emails that mentioned a person’s name had an average open rate of 38.45% while emails that didn’t mention a name had an open rate of 39.49%.

When you combine these figures and calculate the increase rate, you discover that by not including a person’s name in your subject line, you increase your open rate by 9.60% on average.

Sources: GetResponse, BuzzStream

8. Email subject lines that include the word “invitation” have an average open rate of 56.76%

GetResponse analyzed over 4 billion emails and discovered that emails that included the word “invitation” in their subject lines had an average open rate of 56.76%, the highest of all common phrases marketers use in their emails.

These are the top 10 highest-performing phrases to include in your subject lines, according to GetResponse’s data:

• invitation – Emails that used this word in their subject lines had an average open rate of 56.76%

• month – 53.88%

• now – 52.52%

• wanted – 51.53%

• newsletter – 51.29%

• update – 49.49%

• news – 48.05%

• day/week – 48.02%

• prize – 47.58%

• infographic – 47.44%

And these are the lowest-performing phrases:

• tested – 22.64%

• unlimited – 23.22%

• powerful – 26.81%

• massive – 28.23%

• guaranteed – 28.33%

• lifetime – 32.37%

• bargain – 32.64%

• pdf – 33.41%

• re: – 33.48%

• unique – 34.74%

Source: GetResponse

9. Email subject lines that include bracketed text have an average open rate of 50.75%

According to BuzzStream’s data, emails that included bracketed text, like “[Expert quote],” at the beginning of their subject lines had an average open rate of 52.08%.

Emails that included bracketed text at the end of their subject lines had an average open rate of 49.42%.

This means emails that included bracketed text had an average open rate of 50.75%.

Source: GetResponse

10. Mentioning the word “exclusive” in your subject line increases open rates by 45.75%

According to BuzzStream’s data, emails that included “exclusive” in their subject lines had an average open rate of 54.16%.

Emails that did not mention the word “exclusive” in their subject lines had an average open rate of 37.16%.

This means emails that included the word “exclusive” had an open rate that was 45.75% higher than emails that did not include this word on average.

Source: BuzzStream

11. Email subject lines that have no emoji have an average open rate of 40.78%

This is in comparison to subject lines that do have an emoji. Subject lines that use emojis have an average open rate of 39.74%.

This minor difference means that although email subject lines that don’t have an emoji perform slightly better, the presence of an emoji doesn’t really impact open rates.

Furthermore, these figures are the average of the two sources I cited for this statistic.

In GetResponse’s study, they discovered that emails that have emojis in their subject lines have an average open rate of 37.50%.

BuzzStream’s study revealed an open rate of 41.98%.

It’s also worth noting that GetResponse states that 74.98% of the 4.4 billion emails it analyzed contained no emojis in their subject lines compared to the 25.02% that did.

Sources: GetResponse, BuzzStream

12. The beer emoji has the highest open rate at 53.57%

BuzzStream dug a little deeper in its study by identifying the open rates for some of the most widely used emojis customers used in their subject lines.

They discovered that the beer emoji had the highest open rate at 53.57% while the sun emoji had the lowest at 38.06%.

Here’s the full list:

• (beer) – Emails that included this emoji in their subject lines had an average open rate of 53.57%
• ️ (shopping) – 49.74%
• ✈️ (airplane) – 48.81%
• ✨(sparkles) – 46.23%
• (running shoe) – 44.91%
• ☀️ (sun) – 38.06%

Interestingly, emails that contained the sparkle or sun emojis in their subject lines had the highest reply rates.

The sparkle emoji earned marketers a reply rate of 4.49% while the sun emoji earned a reply rate of 3.38%.

This is in comparison to the beer emoji’s reply rate, which was only 0.71%.

Source: BuzzStream

13. Including the word “video” in your subject line increases open rates by up to 13%

Data reported by MediaPost reveals that emails that used the word “video” in their subject lines had open rates that were between 7 and 13%.

Furthermore, these emails had 21% higher conversions and 24% higher order values.

Source:MediaPost

Consumer-Centric Statistics

14. Just under 80% of consumers think it’s unacceptable if your subject line contains spelling errors

MarTech conducted a survey and asked consumers what they feel is most unacceptable in emails.

They discovered that the most irritating thing you can do with your subject line is include spelling errors.

Just under 80% of consumers think it’s unacceptable if a subject line contains spelling errors.

Over 75% think it’s unacceptable if your subject line contains grammatical errors.

Source:MarTech

15. Over 60% of consumers think it’s unacceptable to not include a subject line in your email

When it comes to subject lines, over 60% of consumers think it’s unacceptable to not include a subject line in your email.

Here are other things consumers find unacceptable. These responses received over 60% of votes each:

• Excessive punctuation
• Profanity
• Different font sizes
• All caps subject line
• Irregular fonts
• Slang
• Different font colors

These responses received fewer votes:

• Verbosity (over 40%)
• All lowercase subject lines (over 40%)
• Smiley faces (around 30%)
• Conciseness (under 20%)

Source: MarTech