The word ‘complaint’ suggests bad practices and unhappy customers, yet when it comes to email marketing and your spam complaint rate, it’s not as hostile as it sounds.
That said, marketers should monitor their spam complaint rates because if they’re allowed to slide, it can soon affect your campaign’s deliverability.

What is a complaint rate?

A spam complaint rate is a measure of how many of your email recipients mark your messages as spam (or junk email).

Your email client wants to know which messages are useful to you and which aren’t. By monitoring your behaviour, they get a clear picture of the emails you read and engage with and those you delete right away, or worse still, send to your spam or junk folder.

Your email service provider gathers information to help deliver a better experience for you. But it doesn’t stop there. They also use that information to figure out which organizations are sending out genuine marketing messages and information.

Those emails considered spam are noted not just on your machine but for all users of their service, building a far clearer picture of who’s sending all the spam.

The power behind the spam button

Because the information the ESPs gather is so important to them, they make it as easy as possible for users to dump their most annoying and irrelevant emails.

The problem here for email marketers is that they’ve made it far easier to junk your messages than to unsubscribe from your lists.

All email marketers appreciate that their customers can go two ways over time—they’ll become more loyal than ever or lose interest in your brand or product.

When recipients lose interest, the ideal for you is for them to unsubscribe. However, the junk button in their toolbar is far easier to click than finding an unsubscribe link and following the unsubscribe process.

Especially when they receive 20, 30, 40 or more unwanted messages each day.

How to calculate your spam complaint rate?

It’s a pretty simple calculation. Your spam complaint rate is how many recipients out of all those that receive your email mark it as spam.

Spam complaint rate = Number of recipients who mark it your message as spam / Total number of message recipients

Let’s say you send out your latest campaign to 50,000 email addresses. 500 of them hit the spam button. That makes your spam complaint rate 0.01% (500/50,000).

Nice and easy, right?

What is an acceptable spam complaint rate?

The industry standard for an acceptable complaint rate is 0.1%.

That’s around 5 spam emails out of your 5,000 delivery. Anything over that 0.1% is considered high. If your rate is above 0.1%, then it’s time to get matters in check and beat that rate down.

How spam complaints impact your email deliverability?

Spam rates are how ESP’s learn about the quality of your campaigns.

Email providers continuously monitor your campaigns, and if you earn a high complaint rate, it can take a couple of months to repair the damage—that means lowering the rate and keeping it down.

A high spam complaint rate will affect your sender score and email deliverability. The higher your score, the more of your messages will end up going straight to your recipients’ spam folders, bypassing inboxes, missing out on being read, and losing any possible sales and conversions.

Why do subscribers mark emails as spam?

You’d expect anyone that signed up to your mailing list to welcome your messages with open arms (or eyes!), but sadly, it’s not always the case. There are plenty of reasons a subscriber might change their mind or never have been interested in your business at all.

  • The recipient never consented to receive your emails.
  • There was an error submitting their email address, for example, using the wrong suffix or including a spelling or typing error.
  • Emails are too infrequent to be recognized or sent too often, annoying the recipient.
  • They only signed up to take advantage of an offer.
  • Your emails look like spam or are full of spammy terms and offers
  • The email content isn’t what subscribers thought they were signing up for.
  • Your unsubscribe link is too hard to find or too complicated to pursue.

How to reduce spam complaint rate?

This list is directly related to the one above. Every one of the previously mentioned issues needs rectifying to attain the best possible chances of staying out of the junk folders.

1. Never buy, rent or borrow email lists

This is a golden rule of email marketing. You’d think that the more addresses on the email lists you have, the more chance you have of making sales and conversions. Wrong. Unless you can guarantee that those new recipients are interested in your product, they’re just going to see you as junk.

You can’t even guarantee that those addresses are live and active. You’re wasting your time and money. Just don’t.

2. Make it easy and obvious to unsubscribe

Your unsubscribe link should be at the top of your email and easy to spot. Too many senders try to hide the link, assuming that losing a recipient means losing a customer. If they’re not interested—they’re not a customer.

You’re not losing anything by helping them to leave your list. In fact, they’re doing you a favour. It’s a healthier solution than trying to repair a damaged spam complaint rate.

3. Always use a double opt-in registration system

To limit adding subscribers that aren’t committed to you and reduce mistyped, fake, or bad addresses, you should use a double opt-in registration system.

A double opt-in requires subscribers to confirm they want to receive your emails. That way, you know you’re getting genuine contacts.

4. Only send relevant, considered content

Bombarding subscribers with offers, vouchers, and promotions will make you look desperate.

Deliver content that is informative and relevant to your subscribers. They’ll spot a good deal when there is one, which isn’t always down to price.

5. Avoid spam terms and techniques when compiling your messages and subject lines

There are phrases and practices that make your messages look just like spam content. Words like FREE, GIVEAWAY, BUY NOW, AS SEEN ON, BARGAIN, CLICK HERE, DEAL, FREE GIFT, LOWEST RATES, RISK-FREE, ACT NOW, EXCLUSIVE DEAL—oh, and NEVER use all caps.

Be extra vigilant with your subject lines, as this is the first place your messages will be marked down.

Run your emails through a spam checker. These wonderful tools are designed to pick out all the things that the ESPs pick out and tell you how to fix them.

6. Use a custom domain name for your email campaigns

Use the same domain that your subscribers signed up to and keep it consistent. Both subscribers and software will recognize a regular sender, and be less likely to mark you as a spammer.

7. Stick to a healthy schedule

Both subscribers and providers feel more comfortable with a regular schedule. Depending on your product, typical subscriber, and list count, this can vary. Make sure you don’t overwhelm your subscribers yet still send enough information to keep them interested.

Your service provider will consider you trustworthy when it recognizes a recurring schedule—not random blasts to hundreds of thousands of accounts.

Remember to clean your list

Keep your lists clean and healthy at all times:

Make sure that you remove inactive subscribers manually, and send reengaging campaigns.

Take off your list the recipients that do not engage with your content. 

Using an email cleaner like Bouncer will help you remove invalid email addresses.

A clean list—sending only to active recipients—boosts all your email marketing scores, from opens and clicks to spam rates, deliverability, and conversions.

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