New email marketers often ask us, “How should I write my subject lines so that more recipients will open my emails?” In order to answer that question, we analyzed more than 40 million emails sent from customers through MailChimp, and singled out the ones with the highest and lowest open rates. Then we pulled 20 from each pile, and put their subject lines in a side-by-side comparison. The highest open rates were in the range of 60-87 percent, while the lowest performers fell in the dismal 1-14 percent range. Do you see a pattern below?

Best Open Rates (60%-87%) Worst Open Rates (1%-14%)
1. [COMPANYNAME] Sales & Marketing Newsletter 1. Last Minute Gift - We Have The Answer
2. Eye on the [COMPANYNAME] Update (Oct 31 - Nov 4) 2. Valentines - Shop Early & Save 10%
3. [COMPANYNAME] Staff Shirts & Photos 3. Give a Gift Certificate this Holiday
4. [COMPANYNAME] May 2005 News Bulletin! 4. Valentine's Day Salon and Spa Specials!
5. [COMPANYNAME] Newsletter - February 2006 5. Gift Certificates - Easy & Elegant Giving - Let Them Choose
6. [COMPANYNAME] Newsletter - January 2006 [ *|FNAME|* *|LNAME|* ] 6. Need More Advertising Value From Your Marketing Partner?
7. [COMPANYNAME] and [COMPANYNAME] Invites You! 7. [COMPANYNAME] Pioneers in Banana Technology
8. Happy Holidays from [COMPANYNAME] 8. [COMPANYNAME] Moves You Home for the Holidays
9. ATTENTION [COMPANYNAME] Staff! 9. Renewal
10. ATTENTION [COMPANYNAME] West Staff!! 10. Technology Company Works with [COMPANYNAME] on Bananas Efforts
11. Invitation from [COMPANYNAME] 11. [COMPANYNAME] Update - A Summary of Security and Emergency Preparedness News
12. [COMPANYNAME] Jan/Feb 2006 Newsletter 12. Now Offering Banana Services!
13. Website news - Issue 3 13. It's still summer in Tahoe!
14. Upcoming Events at [COMPANYNAME] 14. [COMPANYNAME] endorses [COMPANYNAME] as successor
15. [COMPANYNAME] Councils: Letter of Interest 15. [COMPANYNAME] Holiday Sales Event
16. [COMPANYNAME] Coffee Exchange - Post-Katrina Update 16. The Future of International Trade
17. We're Throwing a Party 17. [COMPANYNAME] for your next dream home.
18. October 2005 Newsletter 18. True automation of your Banana Research
19. [COMPANYNAME]: 02.10.06 19. [COMPANYNAME] Resort - Spring into May Savings
20. [COMPANYNAME] Racing Newsletter 20. You Asked For More...
* Study only included campaigns sent to at least 100 recipients.

Observations

On the “best” side, you’ll notice the subject lines are pretty straightforward. They’re not very salesy or pushy or slimy. Heck, some people might even say they’re boring. On the “worst” side, however, notice how the subject lines read like headlines from advertisements you’d see in the Sunday paper. They might look more creative, but their open rates are horrible. It’s as if those email marketers assumed that subject lines have to jump off the screen and GRAB THE READER’S ATTENTION! or something. Unfortunately, most people get so much junk mail in their inbox, anything that even hints of spam gets thrown away immediately.

The Secret Formula for Subject Lines

So what’s our advice when it comes to email subject lines? This might sound dead-simple, but here you have it: Your subject line should (drum roll please) describe the subject of your email. Yep, that’s it.

Always set your subscribers’ expectations during the opt-in process about what kinds of emails they’re going to receive. Don’t confuse newsletters with promotions. If your email is a newsletter, put the name and issue of the newsletter in your subject line. Because that’s what’s inside. If your email is a special promotion, say so in the subject line. Either way, just don’t write your subject lines like advertisements.

When it comes to email marketing, the best subject lines tell what’s inside, and the worst subject lines sell what’s inside.

Setting Expectations

So does that mean your subject lines should be stale and uncreative if you want high open rates? Not necessarily. In this study, we actually saw some campaigns that used more creative subject lines (like the ones on the “bad” side of our table) but had decent open rates. The difference seemed to be in the expectations that were set for the emails.

For example, traditional email newsletters are for “soft-selling.” They build relationships with your customers, and they’re great if your products have a long sales cycle. Use them to slowly soften your customers for the sale, or to make them feel really good about your brand. If your recipients signed up for these kinds of emails, don’t expect them to be enthusiastic when, out of the blue, you send an email with a subject line like, “10% Discount! Open Now!” If you’re sending newsletters, keep your subject lines simple, straightforward, and consistent.

On the other hand, if your subscribers specifically opted in to receive special offers and promotions from your company, there's nothing wrong with saying there’s a 10-percent off e-coupon inside. They’re already expecting a “hard sell” from you. It’s when marketers send promotional emails to their entire newsletter list when things go wrong. The idea is to create a totally separate opt-in list for those who want to receive promotional emails only. You might even want to segment your promotions list into smaller, more focused groups before you send a campaign (don’t send an offer for purses and high-heeled shoes to the men on your list).