Klaviyo bounce rate: hard vs soft bounces and what's too high

What is a bounce in Klaviyo?

A bounce is an email that wasn't delivered or was rejected by the recipient's inbox provider. Klaviyo splits them into two types, and they work very differently.

• Hard bounce: the email can't be delivered for a permanent reason. Think a misspelled address or one that doesn't exist.
• Soft bounce: the email couldn't be delivered for a temporary reason. Think a full inbox or a mail server that's down for a bit.

The difference matters because a hard bounce will never fix itself. A soft bounce usually will.

What's a good bounce rate in Klaviyo?

Below 1.0%. That's the number in Klaviyo's deliverability best practices reference, and it's the one I'd hold you to.

The math is simple: bounced emails divided by total emails sent. If you sent a campaign to 20,000 people and 150 bounced, that's 0.75%. You're fine. If 400 bounced, that's 2%, and something upstream needs fixing.

Klaviyo doesn't publish a single number where it steps in. What it does say is that if you keep sending campaigns with high hard bounce rates, your sending reputation can suffer and Klaviyo may disable your account. Inbox providers read high hard bounces as a sign you're not cleaning your list, or that there's something wrong with how you grow it.

Bounce rate also feeds Klaviyo's deliverability score, along with opens, clicks, unsubscribes and spam complaints from the last 30 days. For the other numbers in that picture, see my post on what a good unsubscribe rate is.

When does Klaviyo suppress a bounced profile?

• Hard bounces: suppressed automatically, on the first one. No waiting period.
• Soft bounces: suppressed after 7 consecutive soft bounces. Klaviyo only counts soft bounces from the past 2 years, and one successful delivery resets the streak.

Profiles suppressed for either reason get removed from the lists they're on. And a hard bounce suppression doesn't go away if that address subscribes again later. Klaviyo also won't send transactional flow emails to profiles suppressed for bounces or invalid addresses.

One more thing worth knowing: Klaviyo uses hard bounce history across its whole sending infrastructure to flag suspicious addresses. So it can skip an address in your account that has never bounced for you, because it bounced for someone else.

If you're seeing a lot of suppressed profiles and want to know what each reason means, I broke them all down in Klaviyo suppressed profiles.

Do bounced profiles cost me money in Klaviyo?

No, on a standard email plan. Klaviyo says suppressed email profiles don't count toward your plan's active profile limit. Active profiles are ones with an email address that can receive email marketing, and a bounced, suppressed profile can't.

The exception Klaviyo notes is billing on its Advanced KDP plan, which is based on total profiles, including suppressed ones.

Where do I see bounces in Klaviyo?

A few places, depending on what you're looking for:

• Account-wide: Analytics, then Deliverability, then Email, then Bounce details. You get the top bounce categories and a bounce report broken out by type, inbox provider and category.
• One campaign: the campaign's Recipient activity tab, then Bounced.
• One flow: the flow's Performance, then View details, then Recipient activity.
• One person: their profile's activity log, where the activity details show the bounce type.
• Everyone suppressed: Audience, then Profiles, then view suppressed profiles and filter by "Email bounced."

The deliverability hub also breaks results down by inbox provider. If bounces jump at one provider and not the others, that's where to dig. I walk through that view in Klaviyo deliverability by inbox provider.

Why is my Klaviyo bounce rate high?

Klaviyo groups bounce reasons into categories like invalid address, mailbox unavailable, reputation, content, message size, frequency or volume, technical, and unclassified. In practice, a high rate on a Shopify brand usually comes down to one of these:

1. Bad addresses getting in. Typos at checkout, fake emails entered to grab a discount, or giveaway sign-ups. Klaviyo warns that giveaways can bring in unengaged and fake emails.
2. An imported list. Old customer lists from a previous platform, or worse, a bought list. Klaviyo is blunt: it's never okay to buy lists. Also note that imports don't trigger double opt-in.
3. Mailing old, dead addresses. People who haven't engaged in a year or two are more likely to have abandoned that inbox.
4. Reputation or technical issues. If a provider is rejecting you, the bounce category will say so. That's a deliverability problem, and it's covered in why your Klaviyo emails are going to spam.

How do I lower my bounce rate?

Start where the bad addresses come in, then deal with what's already there.

Fix the source first

This is where I'd push back on most founders. Remove the obviously bad profiles, sure. But founders over-focus on cleaning the list instead of capturing better profiles in the first place. If your signup form is pulling in fake emails for a discount, cleaning the list every month just means you're cleaning it forever.

Look at where your recent bounces signed up. If it's one popup, one giveaway or one import, fix that. My guide to growing your email list covers capturing people who actually want to hear from you.

A note on double opt-in

Klaviyo strongly suggests double opt-in to validate addresses, and it will cut down on typos and fakes. I still run single opt-in for email unless a brand has a very specific reason not to. If someone entered their email, they want to be on the list, and many people never finish both steps. I explain the tradeoff in Klaviyo double opt-in. If bounces are a real problem from one specific source, fix that source before you put a confirmation step in front of everyone.

Clean up repeat soft bouncers

Don't wait for Klaviyo's 7-in-a-row rule. Klaviyo's own suggested cleanup is a segment of people who can receive email marketing and have bounced at least 4 times in the last 90 days, consecutive or not. Exclude that segment from campaigns, or suppress it.

Stop mailing people who've gone cold

Klaviyo recommends a sunset flow so unengaged people come off before their mailboxes go invalid. Here's how I'd build a Klaviyo sunset flow.

Check the technical basics

Klaviyo's list also includes keeping email size below 110KB, using branded links instead of link shorteners, warming your sending, and setting up SPF, DKIM and DMARC.

FAQ

WRITTEN BY Jack White

Founder of Bardown Digital, a Chicago-based Klaviyo email and retention agency for Shopify brands. He's worked with brands doing $500K to $100M a year, with $100M+ in email-attributed revenue across them.

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