It’s a common misnomer that we’ll ever see all the real email complaints on any email campaign.
Additionally, it’s a widely shared metric that .1% (or 1 per 1000) complaints is the threshold of email delivery or safety.
Newsflash. It’s not even close.
Here’s the real math:
As email marketers, we cannot afford to exceed a complaint threshold on ANY ONE ISP (Yahoo, AOL, Hotmail) of more than this:
1 complaint per 1000 mailed @10% open rate
2 complaints per 1000 mailed @20% open rate
3 complaints per 1000 mailed @30% open rate
If you send out 10,000 pieces of mail to Yahoo, and get a 10% open rate, you can afford 10 complaints.
However, this is where it gets really interesting. If you send 10,000 emails and get a 5% open rate and get 10 complaints, that’s well over the safe limit.
If your email had opened to 10%, you would have 20 complaints. If your email had opened to 20%, you’d have 40 complaints or .4% which will quickly damage your sender reputation.
Many ISPs will actually send you a warning shot by pumping the brakes at a very low single digit open rate when they see a campaign complaining above these limits on the first one thousand opens.
If your ESP does not give you a realtime delivery report like this image below (by mailing), replace your ESP. All Earnware email systems expose domain-based delivery metrics like this as a standard feature.
Since we can’t see our complaints on Gmail we have to use unsubscribes as a gauge. As a guide, 20% (or 1/5) of your unsubscribes are usually complaints. Now keep in mind, this is the top of the limit. You’ll want to operate well below the limit to enjoy the best email delivery and inboxing you really want. So, here’s the same complaint limit scale using unsubscribes as a gauge.
5 unsubscribes per 1000 mailed @10% open rate
10 unsubscribes per 1000 mailed @20% open rate
15 unsubscribes per 1000 mailed @30% open rate
If this doesn’t make perfect sense, ask questions until the math sinks in.