If you’ve done any email marketing in the past, you’re probably familiar with the terms “open rate” and “click-through rate.” The open rate is the percentage of unique opens compared to the total number of messages delivered to your list. The click-through rate (CTR) is the number of people who clicked on a link within your message, as measured against the total number of emails.

Most people measure the success of an email campaign by the CTR, and while that is important, you must have people opening your email before they can click on anything!

Email open rates average between 15% and 30% according to Mailchimp benchmark reports across most industries. And it’s no surprise that specific personal interest topics like religion and hobbies trend higher, while marketing topics like ecommerce and coupon offers trend lower. Emails featuring a “deal of the day” have the lowest open rate of all according to Mailchimp.

One way to increase your open rate is to fine tune your subject line. Super Office cites that according to their research, 33% of email recipients open an email based on the subject line.

Here are 3 types types of subject lines proven to be effective in increasing email open rates. This is not an exhaustive list, just a few good ideas to get you thinking!

  1. Fear of Missing Out Subject Lines

One psychological principle that is practically impossible to resist is the fear of missing out. Humans tend to associate limited availability with exclusivity. If something is difficult to acquire, we assume it’s because it’s better than whatever we already have.

In other words, an item’s availability influences our determination of quality of the product. When items are scarce, we perceive them as more valuable and thus, more desirable (and we certainly don’t want to miss out on something valuable, exclusive or fleeting!)

READ: For a Limited Time Only – Using the Scarcity Principle in Marketing

Here are some great sample subject lines from OptIn Monster that use the fear of missing out:

  • Warby Parker: “Uh-oh, your prescription is expiring”
  • JetBlue: “You’re missing out on points.”
  • Digital Marketer: “[URGENT] You’ve got ONE DAY to watch this…”
  • Digital Marketer: “Your 7-figure plan goes bye-bye at midnight…”
  • Digital Marketer: “[WEEKEND ONLY] Get this NOW before it’s gone…”
  • Jersey Mike’s Subs: “Mary, Earn double points today only”
  • Guess: “Tonight only: A denim lover’s dream”


  1. Funny/Witty Subject Lines

Funny or witty subject lines take a bit more creativity to compose, but they can really pay off! Think of a play on words or reference to popular culture that you can incorporate into the phrase.

Here are some funny email subject lines from OptIn Monster to make your subscribers laugh:

  • Eater Boston: “Where to Drink Beer Right Now” (Sent at 6:45am on a Wednesday.)
  • OpenTable: “Licking your phone never tasted so good”
  • Groupon: “Deals That Make Us Proud (Unlike Our Nephew, Steve)”
  • The Muse: “We Like Being Used”
  • Warby Parker: “Pairs nicely with spreadsheets”
  • UncommonGoods: “As You Wish” (A reference to the movie The Princess Bride.)
  • Travelocity: “Need a day at the beach? Just scratch n’ sniff your way to paradise…”
  • TicTail: “Boom shakalak! Let’s get started.”
  • Thrillist: “Try To Avoid These 27 People On New Year’s Eve”
  • Baby Bump: “Yes, I’m Pregnant. You Can Stop Staring At My Belly Now.”
  • Gozengo: “NEW! Vacation on Mars”
  • The Hustle: “Look what you did, you little jerk…” (This one’s a reference to the movie Home Alone. We hope.)


  1. Pain Point Subject Lines

Creating buyer personas to represent your typical customers, can help you identify their paint points. Use those pain points to get subscribers to open your emails by solving those problems for them.

READ: How to Create Buyer Personas and Why They’re Important for Branding (Now, More than Ever!)

Here are some examples of email subject lines from OptIn Monster that bring out the subscriber’s pain points and offer a solution:

  • Pizza Hut: “Feed your guests without breaking the bank”
  • IKEA: “Where do all these toys go?”
  • IKEA: “Get more kitchen space with these easy fixes”
  • HP: “Stop wasting money on ink”
  • Sephora: “Your beauty issues, solved”
  • Uber: “Since we can’t all win the lottery…”
  • Thrillist: “How to Survive Your Next Overnight Flight”
  • Guess: “Wanted: Cute and affordable fashions”
  • Evernote: “Stop wasting time on mindless work”
  • Duolingo: “Learn a language with only 5 minutes per day”


When you’re crafting your email subject line, it’s also important to keep in mind which words NOT to include. We’ve listed a few notable examples below, but spam filters are getting more and more sophisticated in their sensitivity to trigger words in email subject lines. Hubspot offers a guide for how to build a better email newsletter with real-life up-to-date examples.

Here are a few words to avoid:

  • Money back
  • Get paid
  • Cash
  • Dollars
  • Price
  • Big bucks
  • Credit or Debit
  • Profit
  • $$$
  • Marketing
  • Limited time
  • Get it now
  • Once in a lifetime
  • For new customers only
  • Offer expires
  • Deal ending soon
  • Fantastic
  • The best
  • Perfect
  • Unbelievable
  • Wonderful
  • You will not believe your eyes!
  • Free
  • 100% off
  • Allowance
  • Gift included
  • Rebate
  • 0 down

Do you have some spam words to add to our list? Tell us in the comments below!

The bottom line? Get creative with your email subject lines! You’ve got to think outside the box to cut through the inbox clutter. Try a tactic like fear of missing out, funny/witty subject lines or addressing pain points, and remember to avoid spam words like those listed above.

Even a small percentage increase in your open rate can make a big difference in your CTR and resulting conversion rate, so it’s worth putting in the extra time and effort. Happy emailing!