How to reduce spam complaint rates

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You will learn

Learn about spam complaint rates, and how you can reduce them.

Spam complaint rates measure how often recipients mark your emails as spam. A high spam complaint rate is something to act upon immediately as this will hurt your deliverability performance and sender reputation. In this article, you will learn more about what spam complaint rates entail and how to minimize them over time.

This article specifically focuses on email spam complaint rates. If you are instead focusing on SMS deliverability performance, head to Campaign SMS and MMS Benchmarks. You can also learn more about SMS laws and regulations here.

What is a spam complaint rate?

Spam complaint rate measures how often subscribers mark your emails as spam. The calculation for spam complaint rate is as follows:

  • Spam complaint rate = the number of people who mark your email as spam out of the number of people who receive the email

Why spam complaints rates matter

When someone marks your emails as spam, this signifies to inbox providers that you are sending content to people who do not wish to receive it, and they will be more likely to send your emails directly to spam rather than an inbox in the future. Spam complaints are viewed as more dire than when someone unsubscribes from your marketing, and a rise in spam complaints should not be taken lightly. To maintain a good sender reputation, monitor spam complaint rates closely, and when you see a rise, take action immediately to lower this metric.

A great spam complaint rate is less than 0.05%. For more information on what qualifies as good (and bad) for deliverability metrics, head to our article, How to Monitor Deliverability Performance.

How to decrease spam complaint rates

Some key strategies to decrease spam complaint rates include:

  • Make your unsubscribe link easily accessible
  • Enable double opt-in
  • Enable global unsubscribes
  • Avoid spammy subject lines
  • Ensure that your emails render for all users

Make your unsubscribe link easily accessible

Always include an unsubscribe link and make it easy to find in your emails. If someone wants to opt-out of marketing from your brand and is unable to find this link, then they are more likely to mark your email as spam. A spam complaint hurts your deliverability far more than an unsubscribe; thus, it is best practice to make this easily visible.

For example, do not design your link to have a light font on a white background or place it somewhere deep within the copy of the email. Instead, have this link at the beginning or end of your emails (or both) and make the colors stand out for ease of reading and accessibility.

Having an unsubscribe link is mandatory. If Klaviyo detects that you do not have one, we will automatically include it in your email. That said, you can edit this link and add it where you best see fit.

Enable double opt-in

We highly recommend that you enable double opt-in in your account. Both are found within the settings of your main subscriber list. To navigate there, select your list and click Settings. Then scroll down to Opt-in Process.

Double opt-in controls within list settings page

Double opt-in is a process through which a new subscriber must confirm their subscription before being added to your list. This is enabled by default for all Klaviyo lists, and we recommend keeping it on unless you have a specific use case that calls for single opt-in. For more information, head to our Guide to the Double Opt-In Process.

Enable global unsubscribes

We also highly recommend that you enable global unsubscribes for your lists in Klaviyo. When global unsubscribes are enabled, anyone who unsubscribes from an email will be globally unsubscribed and suppressed from all lists. Again, click into your desired list and select Settings. Then, scroll to Unsubscribes.

Checkbox to disable global unsubscribes

Globally suppressed profiles will remain intact and appear in lists, but they will no longer receive emails. You can remove those suppressed emails from your lists by clicking Manage List > Remove Suppressed Profiles.

If you do not have global unsubscribes on, then someone may unsubscribe from an email assuming they will never receive more communication from your brand; however, if they are on multiple lists or qualify for a flow, they can still be emailed and will be more likely to mark your content as spam. As a result, it is best to enable this within list settings.

You can access a direct link to a global unsubscribe page by selecting Account > Settings > Email; then, scroll down to the Consent section of this page. Send this link to allow subscribers to opt-out of all future sends.

Global unsubscribe page URL

Do not use spammy subject lines

Another best practice to lower spam complaint rate is to avoid subject lines that may sound like they come from spammers. Not only will this cause your recipients to think you send spam and mark your emails as such, but this may also raise suspicion among inbox providers.

Inbox providers have spam filters that automatically send suspicious emails to the spam folder rather than the inbox. There are a lot of words that trigger spam filters, but in general, avoid the following spam-triggers:

  • All capital letters (e.g., FREE MONEY NOW)
  • Using a lot of symbols (e.g., 100% FREE MONEY!!$$$)
  • Including just one large image in your email with little, or no, text
  • Implementing eye-catching or spam-triggering phrases (e.g., JUST THIS ONCE FOR A LIMITED TIME ONLY or ACT NOW!!!)

For more information on how to avoid spammy subject lines, head to this blog post. For inspiration on how to create great subject lines, head to this live training session.

Ensure your emails render for all users

Always account for mobile and desktop layouts for your emails. If there are issues on either layout, then customers who see the improperly rendered emails are more likely to mark them as spam.

A higher-than-usual spam complaint rate may also be a sign of email clipping. For example, Gmail clips emails that are greater than 102 KB in size. Be cognizant of this and adjust your email design accordingly to decrease the size and avoid frustrating recipients.

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