4 tips to write a subject line that boosts your email open rate

Thuc Do
3 min readDec 1, 2021

You’re reading an excerpt from Fiction Agency’s blog, where the intention is to share actionable copywriting guides, tips and insights — 800 words later, you’re armed with what you need to elevate your own brand communications.

The average email open rate is around 20%.

This metric is arguably the most important when it comes to email marketing.

After all, if you can’t get someone to open the email, how can you entice them to click and convert?

We’re experienced in not only writing email copy (just one service we provide) but also assessing the post-send stats.

Before we get to actually writing the email subject line, here are 3 best practices:

  1. Write 3–5 options for each email
  2. Consider A/B tests when sending (or just get some consensus from your team on their favourite subject line)
  3. ALWAYS test send or use the preview function to ensure the subject line isn’t cut off

So now, here are 4 tips for writing a subject line that will improve your email open rate:

Keep it simple and succinct

Contain your subject line to 6–8 words to avoid having it cut off, especially as half of emails are read on a mobile phone.

Consider if you could truncate your subject line to even 1–3 words; this will create negative space in a busy inbox, helping you grab attention.

Copy winning blog title formulas

What makes an effective blog title also makes for an effective email subject line.

Here are 3 models you can use:

  1. The list (and include numbers). E.g. 7 essentials for backpacking.
  2. The question. E.g. Do you carry a snake bandage?
  3. The solution. E.g. Here’s how to treat a snake bite.

Be playful or be provocative

Make your reader smile (even giggle) with a bit of cheek and consider if, when and how you would use emojis.

Or entice with an innuendo like W Hotels with ‘Our beds aren’t just for sleeping…’ and Frank Body; we’ve never used a Frank Body product but we’re on their list just because their emails are so damn enjoyable to read.

By being playful or provocative, you will spark curiosity in the reader — hopefully enough to boost your email open rate!

Boost your email open rate by calling out ‘free, new, on sale, save, win’

Call out specials immediately because everyone (everywhere) loves a deal.

For sales and savings, include the dollar or percentage amount in the subject line.

Use words and phrases such as ‘now’ and ’36 hours only’ to inject urgency and appeal to that scarcity (and FOMO) mindset.

Use phrases such as ‘limited edition/release’, ‘you’re invited’ and ’small batch’ to create exclusivity.

If it isn’t aligned with your brand to say ‘free’, here are some alternatives:

  • Complimentary
  • Shipping’s on us
  • Gift/present

4 real-life examples (but reworked)

Here are some email subject lines we found in our very own inbox. We’ve reworked them and explained why to land the above tips for you.

Take $20 Off | Backpacks for wherever (and whenever) you go.
Reworked: Take $20 Off All Backpacks
Reason: Too long so gets cut off. The ‘wherever (and whenever) you go’ is cute and perfect for brand tone and can be placed in the preview text.

Happening now: Up to 30% off with our mid-season sale.
Reworked: Happening now: 30%* mid-season sale.
Reason: Too long so the most important word, ‘sale’, is cut off. Delete filler words, ‘with’ and ‘our’.

Have you tried these five ways to get active in nature
Reworked: 5 ways to move in nature
Reason: Too long so gets cut off and use the actual number ‘5’.

Ditch the couch for caves, coastlines and wild-as forests to win amazing prizes
Reworked: WIN: FitBit & an All Parks pass
Reason: Too long so the most important part, ‘win’ is cut off. This subject line is too descriptive and superfluous; it isn’t clear what the email is about.

‘Applaud’ if you found this article useful and if you have questions, ask away in the comments. You can also find us at www.fiction-agency.com and www.instagram.com/fiction_agency.



Thuc Do

Writer and director of Fiction Agency, a copywriting agency that creates with sophistication and strategy. Find me on Substack: wellspring1.substack.com