Email Bounce Rate
Email bounce rate is the percentage of sent emails that failed to reach the recipient's inbox, calculated by dividing total bounces by total emails sent and multiplying by 100.
What Is Email Bounce Rate?
When you send a campaign, not every email makes it to its destination. Some get rejected by the receiving mail server, and those rejections are called bounces. Your bounce rate tells you what proportion of your list is, essentially, unreachable. A 2% bounce rate on a send of 10,000 emails means 200 of your subscribers didn't receive your message at all. Bounces split into two camps: hard bounces and soft bounces. Hard bounces are permanent failures, usually because the email address doesn't exist, the domain is invalid, or the recipient's server has outright blocked you. Soft bounces are temporary, things like a full inbox or a server that was briefly unavailable. Most email platforms will automatically retry soft bounces a few times before giving up. Hard bounces, on the other hand, should be removed from your list immediately. Keeping them around is one of the fastest ways to damage your sender reputation. Industry benchmarks vary by sector, but a bounce rate below 2% is generally considered acceptable. Anything above that warrants attention. A spike in bounces, especially hard bounces, is often a signal that your list has gone stale, that you've acquired addresses through questionable methods, or that something has changed with a large email provider your subscribers use.
Why It Matters for Newsletters
For newsletter creators, bounce rate is one of the clearest early-warning signals you have. A rising bounce rate quietly erodes your sender reputation with inbox providers like Gmail and Outlook. The more you send to dead addresses, the more those providers start treating you like someone who doesn't maintain their list properly, which can tip you toward the spam folder even for subscribers who are perfectly valid and engaged. There's also a practical economics argument. If you're on a paid email platform, you're likely paying per subscriber or per send. Bounced addresses are dead weight on your bill. Monitoring bounce rate regularly and acting on it quickly, by removing hard bounces and investigating clusters of soft bounces, keeps your list clean, your costs down, and your deliverability intact.
Best Practices
- Remove hard bounces from your list immediately after they occur. Don't wait for your next campaign.
- Set a threshold for soft bounces, typically three to five consecutive failures, before suppressing an address.
- Use double opt-in for new subscribers to validate email addresses at the point of sign-up, which cuts down on typos and fake addresses from the start.
- Run regular list hygiene checks, particularly if a segment of your list hasn't been mailed in several months. Addresses that looked valid in 2024 may have been abandoned or closed since.
- Monitor bounce rate by segment and by acquisition source. A high bounce rate among subscribers from a specific lead magnet or sign-up form often points to a problem with that source.
How Aldus Handles This
Aldus tracks bounce rate at the campaign and list level, flagging hard bounces for immediate suppression so you're never unknowingly sending to dead addresses. If your bounce rate creeps above healthy thresholds, Aldus surfaces that in your deliverability dashboard alongside actionable context, not just a raw number, so you can diagnose whether it's a list age problem, an acquisition source issue, or something worth escalating.