Email bounce rate: Benchmarks, causes & how to improve it

Email bounce rate is the percentage of sent emails that couldn't be delivered to the recipient's inbox and were returned by the receiving mail server. A good email bounce rate is under 2%, and under 1% is ideal. Anything above 5% is a red flag that can hurt your deliverability and put your sending account at risk.

A few bounces are normal. A lot of them are a sign that your list needs attention and that inbox providers like Gmail and Outlook may start trusting you less.

In this article, we'll focus on:

• What email bounce rate is and how to calculate it
• The difference between hard bounces and soft bounces
• What a good email bounce rate is, with benchmarks by industry
• The most common causes of a high bounce rate
• 8 steps to reduce your email bounce rate
• How Transpond helps you keep your bounce rate low
• Answers to common questions about email bounce rate

What is email bounce rate?

Email bounce rate is the percentage of emails in a campaign that were rejected by the recipient's mail server and never reached the inbox. When an email bounces, the receiving server sends back an automated message (a bounce notice) explaining why it couldn't be delivered.

Bounce rate is different from deliverability. A message can be delivered but still land in spam. Bounce rate only measures the emails that were turned away at the door.

How to calculate email bounce rate

To calculate email bounce rate, divide the number of bounced emails by the number of emails sent, then multiply by 100.

For example, if you send a newsletter to 5,000 contacts and 60 bounce, your bounce rate is 60 / 5,000 x 100 = 1.2%.

Most email marketing platforms, including Transpond, calculate this for you on every campaign. It's still worth knowing the formula so you can compare campaigns and spot when something changes.

Hard bounces vs soft bounces

There are two types of email bounces. A hard bounce is a permanent delivery failure, and a soft bounce is a temporary one; there are different ways to handle each.

A simple rule for soft bounces: if an address soft bounces on three to five campaigns in a row, treat it like a hard bounce and stop sending to it. Repeated soft bounces often mean an abandoned inbox.

Hard bounces do the most damage. Inbox providers like Gmail and Outlook see repeated sends to dead addresses as a sign of a poorly managed or purchased list, which lowers your sender reputation.

What is a good email bounce rate?

A good email bounce rate is under 2%, and the best-run lists stay under 1%. Once you pass 2%, it's time to look at your list. Above 5%, many email platforms will flag or restrict your account.

NB: Thresholds based on guidance from ZeroBounce and Truelist.

Average email bounce rate by industry

Average bounce rates vary by industry, mostly because some audiences change email addresses more often than others. B2B lists tend to bounce more because people change jobs and their work addresses stop working.

Source: Mailchimp campaign data, as reported by ZeroBounce. Other datasets put averages higher, at around 2% to 3% (Truelist, 2026), so treat any single number as a guide rather than a target.

The benchmark that matters most is your own. Track your bounce rate campaign by campaign. A sudden jump tells you more than any industry average.

Why your bounce rate creeps up over time

Email lists decay by at least 28% a year, according to ZeroBounce's Email List Decay Report. People change jobs, abandon old accounts and switch providers. So even a list that started clean will bounce more each month unless you look after it.

What causes a high email bounce rate?

Most high bounce rates come down to the quality of your list. The main causes are:

1. Old or unused contacts. Addresses that haven't been emailed in months are far more likely to have been closed.
2. Typos at signup. "gmial.com" and "john@company.con" are hard bounces waiting to happen.
3. Fake or throwaway addresses. Some people enter a disposable address just to get a discount or download.
4. Bought or rented lists. These are full of dead addresses and spam traps, and contacts never agreed to hear from you.
5. Imported data from other systems. Contacts pulled from spreadsheets, events or an old CRM often haven't been checked in years.
6. Missing email authentication. If your sending domain isn't set up with SPF, DKIM and DMARC, receiving servers may reject your emails outright.
7. Spammy content or sudden volume spikes. Sending far more email than usual, or content that trips spam filters, can lead to temporary blocks that show up as soft bounces.

How to reduce your email bounce rate: 8 steps

The fastest way to reduce your email bounce rate is to remove hard bounces after every send and stop bad addresses getting onto your list in the first place. These eight steps cover both.

1. Remove hard bounces after every campaign

Never send to a hard-bounced address twice. Most email platforms suppress these automatically, but check that yours does, and check again after importing contacts.

2. Set a rule for repeat soft bounces

Decide how many soft bounces in a row you'll accept before suppressing an address. Three to five consecutive campaigns is a sensible limit for most small businesses.

3. Use double opt-in on your signup forms

Double opt-in asks new subscribers to confirm their address by clicking a link. It catches typos and fake addresses before they ever reach your list, and it proves people want to hear from you.

4. Verify imported lists before you send

Before emailing a list from an event, a spreadsheet or an old system, run it through an email verification tool. It'll flag invalid, disposable and risky addresses so you can remove them first.

5. Never buy or rent email lists

Purchased lists are the quickest route to a high bounce rate, spam complaints and blocklisting. Grow your list with signup forms, landing pages and lead magnets instead.

6. Authenticate your sending domain

Set up SPF, DKIM and DMARC for the domain you send from. These records prove to inbox providers that your emails really come from you. Since 2024, Google requires all senders to Gmail addresses to authenticate their email, and bulk senders (around 5,000+ emails a day) to use SPF, DKIM and DMARC, keep spam complaints below 0.3% and offer one-click unsubscribe. Yahoo has similar rules.

7. Re-engage or remove inactive contacts

Contacts who haven't opened or clicked in six months or more are more likely to have abandoned their inbox. Send them a short re-engagement campaign. Anyone who still doesn't respond can be removed or moved to a separate, low-frequency segment.

8. Send consistently and warm up new domains

Inbox providers prefer steady, predictable sending. If you're using a new domain or sending to a much bigger list than usual, build up volume over a few weeks rather than sending everything at once.

Tip: Keep an eye on bounce rate alongside open rate, click rate and unsubscribes. A rise in bounces together with a drop in opens is a strong signal your list needs a clean-up.

Keep your bounce rate low with Transpond

Transpond, the all-in-one marketing platform for Capsule, helps you build a clean list from day one and spot problems early.

When an address is invalid or keeps failing, Transpond automatically gives that contact a Bounced status. Bounced contacts stop receiving emails and don't count toward your bill.

Signup Forms and Landing Pages add new contacts straight to your list, so there's no copying addresses by hand and fewer typos.

Capsule CRM sync keeps contact details up to date in real time, so when a customer changes their email in Capsule, your marketing list changes too, while Analytics shows bounces, opens and clicks for every campaign, so you can see when your bounce rate starts to rise.

Spam testing and sending domain setup help you check a campaign before it goes out and authenticate the domain you send from.

Get started with Transpond today and manage your email bounce rate effectively.