Email Marketing - A look at how the words used, the number of words, and the number of characters in a subject line impacts email marketing open rates
In our search to continually improve the open rates of our emails and those we send for our clients I have decided to conduct a review of what research says in regards to how to modify a subject line to increase open rates. In this review I look at data from our own email database and industry reports I was able to collect that address this issue. In my research I look at three things. One the impact of subject line character count on open rates, two the impact of subject line word count on open rates and three how specific words in a subject line increase open rates.
Executive Summary
Key Factors That Influence The Open Rate
- number of words and characters
- the words used and sentence structure
- the sending email address
- what the "From" line says
- how targeted the list is
- timeliness or urgency to the recipients situation
- what the email will reward the recipient if it is opened
- the ability to avoid spam filters
- how many recipients assume the message is spam from the subject line
- how geographic specific the subject line is (such as city, street etc)
- how segment specific the subject line is
Specific Tips
- the optimal character count to include in an email is under 28 or over 100 characters have the best open rates
- subject lines with either 1 or 16 to 20 words appear to have the best open rates
- subject lines that create burning curiosity like "error" have high open rates
- avoid using the words "free", "% off", "percentage off", "help", "reminder", "B2B", "industry" and "business", "coupon" and "voucher"
- using the words "turnover", "profit", "acquisition", "deal" and "revenue" increase open rates for B2B emails
- subject lines phrased as a question can often perform better
- send using a personal email like "This email address is being protected from spambots. You need JavaScript enabled to view it." over a generic email like "This email address is being protected from spambots. You need JavaScript enabled to view it."
- have a person's name over a company name in the from line - view study results
- segment your list and send specific emails to each segment to get a better open rate
- describe a benefit for opening the email right in the subject line
- have an expert look at your email marketing to determine if there are ways to reduce the amount of emails you send that go to spam
- include applicable city or street names in the subject line if possible
The Results
Subject Line Character Count Impact On Open Rates
It is important to note how the open rate appears to decline as you go above about 28 characters. Based on the data it looks like shorter subject lines are better. That being said the going over 100 you might be an increase in both open rate and click through rate based on the results from the Adersta study (read about it below).
Source: Profitworks' email database of marketing emails we send and those that we send for our clients. This database contains over 450 different emails to over 98,000 recipients.
Top 3 Subject Lines
| Subject Line | Open Rate | Proposed Rationale For Why It Was Successful |
| error | 73% | Short and generated curiosity |
| It was nice to meet you - CYP Event | 57% | Timely information as was sent the day after meeting them |
| And the winner is.... | 56% | Information people are interested in, everyone wants to win. The list was also very targeted as it was only sent to those that entered. |
Top 3 Subject Lines From Emails Sent To Over 100 People
| Subject Line | Open Rate | Proposed Rationale For Why It Was Successful |
| Christmas Deal - REM Web Solutions | 34% | Timely information as was sent at Christmas time and included the word "deal" that performs well in B2B segments |
| Enjoying the summer | 32% | Is a question and timely as was sent in the summer |
| Slides from event and details on next free workshop - WRSBOA | 32% | People like to skim the slides from presentations even if they don't attend the event. Email offered information on next event, so email subject line gave two different reasons to open the email. |
Worst 3 Subject Lines
| Subject Line | Open Rate | Proposed Rationale For Why It Was Not Successful |
| Discontinued - Quote of the Month | 1% | Information not of interest, no requirement to open email, all needed information is in the subject line. |
| Save Time - Gold Roast Coffee | 2% | Nothing enticing to generate opens. This email may have also went to a large % of spam folders |
| Last Chance To Win Is Tomorrow | 2% | Reminder emails perform very poorly, especially if use the wording "last chance". No requirement to open email, all needed information is in the subject line. |
Worst 3 Subject Lines From Emails Sent To Over 100 People
| Subject Line | Open Rate | Proposed Rationale For Why It Was Not Successful |
| Fall Deal - Jackets - Unique Embroidery | 3% | Email went to a large portion of spam filters because of the email content. |
| Ergonomics - Gold Roast | 4% | My guess is that ergonomics are not of much interest and that a large portion of people are not even familiar with what ergonomics are. |
| How you can benefit from other businesses | 4% | My guess is that this subject title sounds like one from a spammy online marketing scam. |
Mail Chimp Email Subject Line Study - May 2012
Key Findings
- three words that reduce open rates are "Help", "Reminder" and "Percent Off"
- including localization in the subject line such as city name increases open rate
- long subject lines over 50 characters for targeted segments actually increased open rates
- subject lines phrased as a question often perform better
- sending reminder emails decreases open rate (in the example they noted the open rate fell from 8% to 2.3% by the 4th note on the same event)
Specific Examples - Top 3 Subject Lines
| Subject Line | Open Rate | Rationale |
| Preliminary Floor Plans for Southern Village Neighborhood Circle Members | 93.0% | Timely information. Implied benefit of viewing floor plans early for quick action. Over 50 characters in length and localization in the subject line |
| Your April Website Stats | 92.6% | Timely and useful information |
| Idlewild Camp - Important Travel Information | 90.1% | Information the recipient needs to know immediately before travelling. |
Specific Examples - Worst 3 Subject Lines
| Subject Line | Open Rate | Rationale |
| Final reminder for complimentary entry to attend the West Freelands BCI Cluster Conference 2006 | 0.5% | Has word "Reminder" and subject is too long |
| Tempting August NUSA Specials! | 0.9% | Has the word "Specials" and an exclamation mark. Also includes the words NUSA which people do not know what it stands for |
| SALE ends soon - up to 50% off all bras at Kara! | 1.9% | Has percent off in subject line |
Note: I would argue that a great deal of the impact on these email subject line open rates have to do with how targeted of a list they were sent to. To see an open rate of over 90% the list must be very targeted. For example I am sure the email with the subject line "Idlewild Camp - Important Travel Information, went to only those people that had signed up for the camp.
Source: http://kb.mailchimp.com/article/best-practices-in-writing-email-subject-lines
Adersta Email Marketing Study - July 2012
Key Findings
- subject line with over 100 characters significantly increase click through rates and have high open rates
- subject lines with 16 to 20 words appear to the highest open rate but low click through rates
- the words "coupon" and "voucher" reduce open rates
- the words "% off" and "Summer Sale" increase open rates
- the words "turnover", "profit", "acquisition", "deal" and "revenue" increase open rates for B2B emails
- the words "B2B", "industry" and "business" reduce open rates for B2B emails
Subject Line Word Count Impact On Open Rates
B2B Word Inclusion Impact On Open Rate
Source: http://hosted.adestra.com/adestra/whitepaper/Adestra_SubjectLine_Study_July_2012.pdf
Looking for more email marketing tips? Check out our FREE Email Marketing Guide!
If you are a business that does not use email marketing I would highly recommend you take advantage of this tool. It can be a great marketing tool and is often referred to as the top return on investment marketing initiative for businesses. If you don't know where to start sign up for Aweber or Constant Contact. Both systems are low cost, easy to learn and very effective to use. I think Aweber also has an offer on right now where you can sign up for $1 for a one month trial. Forwebsites built on Joomlathe email marketing programAcymailing is also a great option.
Get Customers Blog - Go To Blog Homepage
My name is Chris R. Keller. I work at Profitworks Small Business Services helping various business to business small businesses in Waterloo and Kitchener Ontario generate new customers. Feel free to connect with me on Google+ or if you are just interested in getting new customers for your B2B small business enter your email in the box provided below and click the "Send Me Free Marketing Insights" button.
Other Articles You Might Be Interested In
1. Email Marketing Guidelines To Generate New Customers
2. The Importance of Email - Why Every Business Should Use Email Marketing
3. Effective Email Templates - Does Putting Images On The Left Or Right Side Improve Results
4. Email Marketing Optimization - Best Time Of Day To Send Emails For Maximum Impressions
