When it comes to fundraising appeal emails, there may be no element more important than the subject line. After all, this is what the recipient sees first, and how it’s crafted can mean the difference between whether or not the email is opened.

No pressure, right?

Before you have a panic attack, here is a semi-exhaustive list of considerations and resources from proven email experts:

1. The law

First, consider the 2003 CAN-SPAM Act. With regards to email subject lines, the CAN-SPAM act requires content compliance. This means that you can’t use misleading or deceptive subject lines. In other words, the content of your subject line must be relative to the body content of the email. For example, you can’t use a subject line like “Hurricane Evacuation Notice” just to generate opens, and then ask for a donation unrelated to a hurricane evacuation.

Not only can recipients mark you as spam, but they can also report you for this violation.

So don’t be deceptive just to get high open rates.

2. Spam filter trigger words and characters

There is much debate over which, if any, words or phrases automatically trigger subject lines. Litmus contends it’s mostly an old wives tale that “free,” all caps and exclamation points automatically flag an email as spam. Don’t be afraid to experiment with emojis, special characters and capitalization.

3. Clean data

If you’re using merge tags, be sure that your data is up-to-date and complete. There’s nothing worse than attempting to personalize an email subject line, only for it to fail and display something like “Dear [FIRST NAME],”.

4. Words humans ignore

A 2013 study by MailChimp found that the following words have a negative impact on open rates in standard deviations:


That same study also found the positive impact that the phrase “Thank You” has on open rates:


This underscores the effectiveness of taking a donor-centric approach in your appeals.

Lastly, the MailChimp study found that words implying time sensitivity correlate to higher open rates:


5. Subject line length and format

Just because you can cram hundreds of characters into a subject line doesn’t mean you should.

A 2012 study by MailerMailer found that subject lines with fifteen characters or fewer, had the highest open rates.

Just look at how the short subject line below stands out amongst several emails:


Source: Wordstream

ClickZ has a list of interesting subject line strategies that include:

  • Non-Sequiturs
  • Lists of Three
  • Shock and Awe
  • Rhymes and Alliteration
  • Create a Common Enemy

HubSpot has a great list of 18 real subject line examples from successful campaigns that you can pull inspiration from.

6. Expert advice only goes so far

It’s normal to feel overwhelmed by all this advice; there’s no shortage of it out there. No one knows your audience better than yourself, so first and foremost lean on past experience to guide you. Look back on past emails and investigate which subject lines performed best for their intended purpose. If you can’t find a clear winner, consider experimenting with some of the ideas above. There are no hard and fast rules that apply to all nonprofits!

How do you approach crafting the subject line for your email appeals? Let me know in the comments below!

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