The Difference Between Hard Bounces and Soft Bounces [FAQs]

When I first tried my hand at email marketing, I was blown away by how many terms I needed to learn. I kept drawing blanks on what terms actually meant for the first few months I was learning about email marketing.

The terms that gave me the most trouble? Hard and soft bounces. 

Sure, I knew that these were email deliverability terms. One was bad, and one was not always bad. And somehow I always got them mixed up with each other (even today, I have to triple check to make sure I'm on-point).

And I suspect I'm not alone. Since hard and soft bounce rates are two of the most crucial email marketing metrics you should be tracking, here's a quick guide to these two email marketing terms.

Hard Bounces vs. Soft Bounces: What's the Difference? 

When an email bounces in general, it means it can't be delivered to an inbox. "Hard" and "soft" designate the two groupings of failures: one's more permanent, and one's less permanent. 

A hard bounce is an email that couldn't be delivered for permanent reasons. Maybe the email's a fake address, maybe the email domain isn't a real domain, or maybe the email recipient's server won't accept emails. There are lots of reasons that an email could be a hard bounce, but the core of it is that it's a permanent failure. You should remove all of these addresses from your list (if you're a HubSpot customer, we'll ensure hard bounce addresses won't receive emails from you so your sender reputation remains in tact). 

A soft bounce is an email that couldn't be delivered because of temporary reasons. An inbox may be full or the email file might be too large, among other reasons. If they get a soft bounce on an email send, most email providers will continue to try to deliver the email over the period of a few days. You should keep an eye on these addresses -- if you notice that the same ones are popping up over and over again, it's best to remove them.

Try to keep your total bounce rate under 2% -- much higher than that, and you'll start noticing some deliverability issues. 

And that's pretty much it. Hard bounces = permanent delivery failures. Soft bounces = temporary deliverability failures. Not as complicated as it first seems, but definitely just as crucial.