Reaching out
How to lower your cold email bounce rate
To lower your email bounce rate, stop sending to addresses that hard bounced, send old lists in small test batches, set up SPF and DKIM on your domain, and keep your list short and current.
By Invenitor team. Updated .
What bounce rate should you aim for?
Hunter says bounces should stay under 2% of all sent emails, and it calls that "a widely adopted benchmark in the cold email industry" (Hunter). Treat this as a rule of thumb. It comes from a vendor, and other vendor blogs give different figures, often without showing their data. Mailbox providers do not publish a limit like this.
What is clear is the direction. If you see a rising bounce rate, something is wrong with your list, and you should deal with it before you send any more. To work out your rate, divide bounces by emails sent and multiply by 100. If you send to 50 people and 2 bounce, your rate is 4%, and you should stop and look.
What is the difference between a hard and a soft bounce?
They need different responses, so read your bounce messages rather than treating them all alike:
| Type | What it means | What to do |
|---|---|---|
| Hard bounce | Permanent. The address does not exist or will never accept your mail. | Remove it right away. Never retry. |
| Soft bounce | Temporary. The mailbox is full or the server is busy. | Retry once or twice. Remove it if it keeps failing. |
| Block | The receiving system refused you. This can be about your domain, not the address. | Stop and check your setup. Look at the message text. |
The bounce message usually explains why, in plain enough words. A note about policy or reputation is a warning about you, not about that address. See hard bounce and soft bounce.
What causes most bounces?
Usually, one of these causes:
- Old lists. People move on, and work mailboxes get closed. See data decay.
- Guessed addresses. A name pattern looks right but often is not.
- Typos in a list that someone typed by hand.
- A former employer's address on an out-of-date profile.
- Bought lists, which often have been used by many others before you.
- Your own sending setup, which can cause blocks that look like bounces.
How do you clean a list before you send?
Do this in order, before you send to anyone on the list:
- Remove duplicates and obvious typos, such as gmial.com.
- Remove everyone on your do-not-contact list.
- Check that the domain matches where the person works now. Look at their profile for the most important names.
- Use a checking tool if your list is more than a few names. Hunter's Email Verifier, for example, is 0.5 credit per address (Hunter pricing). Treat "unknown" and "accept all" results with care. See catch-all address.
- Send to a small batch first, perhaps ten people. Wait a day and read the results.
- Only then send to the next batch, if the first one went well.
Invenitor does not guess addresses and does not run mailbox checks, so it cannot promise that an address will accept mail. Treat each contact as something to check before a large send, as you would from any source.
What should you set up on your domain?
Google says all senders to Gmail must set up SPF or DKIM, and use TLS and valid forward and reverse DNS. Senders of more than 5,000 messages a day must also use DMARC, align their domain, and support one-click unsubscribe (Google sender guidelines). Set up SPF and DKIM even if you send very little. Your email provider has instructions, and it usually takes minutes. See SPF, DKIM and DMARC.
Google's guidelines also ask you to keep spam rates below 0.10%, and never reach 0.30%, as reported in Postmaster Tools. Bounces and spam reports are separate numbers, but they tend to go together, because a poor list causes both.
How do you keep the bounce rate low over time?
Work with short, recent lists. Do not save names for a year. Gather people when you are ready to write to them. Remove hard bounces the same day. Watch your own numbers by batch, so that a problem shows up after ten sends, not after a thousand.
Make one person responsible for the list, even if that is you. Have only one copy of it. When a reply says someone has left, remove them, and ask who took over. That reply is itself useful.
Keep your volume in line with what you can personally write. It helps your bounce rate, and it also matters under Invenitor's Terms, which prohibit unconsented marketing and automated outreach. When you need someone new, a contact on Invenitor is 1 credit (₹2), and only when an email or phone comes back. For the wording that follows, see how to write a first email.
Common questions
- Is a 5% bounce rate bad?
- It is well above the 2% that Hunter calls a widely adopted benchmark. Stop, find the cause, and clean your list before you send more.
- Should I remove soft bounces?
- Retry once or twice, and remove an address if it keeps failing.