If you send email campaigns for long enough, you’ll inevitably run into spam-filter issues. Innocent email marketers who send permission-based emails to people who requested them get spam filtered all the time. Unfortunately, there’s not a quick fix. The only way to avoid spam filters is to understand what spam is and how the filters work. Here’s the rundown courtesy of Mailchimp…


Spam filters look at a long list of criteria to decide whether your email is junk. They might look for spammy phrases like “CLICK HERE!” or “FREE! BUY NOW!” They’ll assign points every time they see one of those phrases. Certain criteria get more points than others.


Here’s a sample of criteria:

  • Talks about lots of money (.193 points)
  • Describes some sort of breakthrough (.232 points)
  • Looks like mortgage pitch (.297 points)
  • Contains urgent matter (.288 points)
  • Money back guarantee (2.051 points)


If your campaign’s total “spam score” exceeds a certain threshold, then your email goes to the junk folder. You’re probably thinking, “What’s the threshold I need to stay under?” Sorry, but the number is different for every server.


As for that list of “spammy” criteria, it’s constantly growing and adapting, because spam filters learn more about junk every time someone clicks the This is spam button in their email program.


Spam filters even sync-up with each other to share what they’ve learned. Though there’s no magic formula, we can help you avoid common mistakes that send newsletters to junk folders.


Avoid these common mistakes

These are the most common mistakes we see new email marketers make, which result in accidental spam filtering:

  • Using spammy phrases, like “Click here!” or “Once in a lifetime opportunity!”
  • Going crazy with exclamation points!!!!!!!!!!!!!!!
  • Coloring fonts bright red or green
  • Coding sloppy HTML, like from converting a Microsoft Word file to HTML
  • Creating an HTML email that’s nothing but one big image, with little or no text (since spam filters can’t read images, they assume you’re a spammer that’s trying to trick them).
  • Using the word “test” in the subject line (agencies run into this when sending drafts to clients for approval)
  • Sending a test to multiple recipients within the same company (that company’s email firewall can only assume it’s a spam attack)
  • Sending a newsletter from your own email account i.e. Outlook.


These tips comes from Mailchimp – one of our preferred email sending programs to use for their reports and ease of use. Read more on them here.