Email Deliverability Rate: Delivery vs Inbox

What is an email deliverability rate?

People say "deliverability rate" for two different numbers, and mixing them up hides most problems. The first is the delivery rate: the share of sent emails that the receiving mail server accepted without a bounce. The second is inbox placement, which is the share that landed in the inbox rather than the spam or junk folder. Mailjet and Litmus both draw this line in their guides on delivery versus deliverability. A message that goes to spam still counts as delivered, because the server accepted it.

That's why a sending report can show almost every message delivered while replies dry up. The delivery rate only tells you the SMTP conversation ended with acceptance. What the mailbox provider did with the message after that (inbox, spam, Promotions tab, quarantine) is decided by its filters, and those filters don't report back to the sender. Campaign Monitor says as much in its own deliverability explainer: it reports an overall delivery rate but can't know what percentage of emails reach the inbox versus spam.

How do you calculate delivery rate and inbox placement?

The delivery rate formula, as Google's AI overview states it citing Litmus, is (delivered emails ÷ emails sent) × 100. Delivered means sent minus bounced, so the bounce count is what moves the number. Bounces come from the receiving server's SMTP reply. A temporary failure, such as a full mailbox or a server that's briefly unavailable, makes the sending server retry. A permanent failure means the address doesn't exist or the message was refused outright. Our guide to email bounce codes and their causes walks through the replies cold senders run into most often.

Metric	Formula	What it tells you	Where you see it
Delivery rate	Delivered ÷ sent × 100	The receiving server accepted the message	Your sending platform's reports, e.g. your Brevo account
Bounce rate	Bounced ÷ sent × 100	Addresses that don't exist, full mailboxes, or outright refusals	Sending platform reports, split into hard and soft bounces
Inbox placement rate	Messages in inbox ÷ messages delivered × 100	Whether filters trusted the message	Only estimated, through seed tests or panel data
Spam complaint rate	Complaints ÷ delivered × 100	Recipients clicking "report spam"	Feedback loops and Google Postmaster Tools

What is a good email deliverability rate?

The benchmarks published by vendors in the current search results cluster high, but they don't agree. PowerDMARC puts a good rate at 95–99% and treats anything below 94% as a warning sign. Validity says at least 85%, with 98–99% ideal. Litmus describes a goal of 90–98%. ZeroBounce says above 90%, with the best results near 99.6%. Google's AI overview, citing Mailjet, calls 98–99% a healthy delivery rate.

Read these figures with two caveats. First, some of them describe delivery and some describe inbox placement, and those aren't the same number. Second, they mostly come from opted-in marketing lists. A cold B2B list hasn't confirmed its addresses through a signup, so it carries more dead mailboxes and role accounts, and its bounce rate shows how good your data is before it shows anything else. If your delivery rate falls, look at the list source first, then at authentication.

Why does a delivered email still land in spam?

Acceptance and placement are separate decisions. Once a server has accepted a message, its filters weigh several signals:

• Authentication: SPF checks whether the sending server may send for the domain, DKIM checks the message's signature, and DMARC requires one of them to align with the visible From domain. If alignment fails, a message can be accepted and still filtered.
• Domain and IP reputation: built from past complaints, bounces and recipient behaviour. A new domain has no history, and a domain that already has complaints carries them forward.
• Volume pattern: a sudden jump from a handful of messages to hundreds a day on a fresh domain looks like a compromised or throwaway sender.
• Content and structure: many near-identical messages, link shorteners, heavy HTML or attachments give filters something to match on.
• Shared infrastructure: if you send through a sender address other people also use, their behaviour affects your reputation too.

Our article on DKIM, DMARC and SPF for cold email senders covers the setup order and the usual alignment mistakes.

How to improve your email deliverability rate

1. 1 Verify the list before you send. Remove addresses that hard-bounced before, along with role mailboxes nobody reads. Bounces drag down your delivery rate and your reputation at the same time.
2. 2 Authenticate the sending domain. Publish SPF, sign mail with DKIM on your own domain, and add a DMARC record. Start with a monitoring policy and tighten it once reports show aligned mail. Google's sender guidelines require authentication from bulk senders.
3. 3 Warm up new domains. Raise daily volume step by step, not all at once, and watch bounces and complaints before each increase.
4. 4 Suppress bounces right away. A hard bounce should never be mailed again, and repeated soft bounces should be treated the same way.
5. 5 Make opting out easy. A visible unsubscribe link gives recipients a way out other than the spam button.
6. 6 Measure placement as well as delivery. Run seed tests and check Postmaster data alongside your platform's delivery report.

Some things don't work. A warm-up tool can't repair a bad list, because once real sending starts, the bounces come back. Changing to a new domain after a complaint spike just restarts reputation from zero. And tweaking subject lines won't fix a DMARC alignment failure. For ramp-up volumes and DNS prerequisites, see our guide on email warm-up daily volumes and DNS setup.

Which tools measure inbox placement?

No single tool gives you a true inbox placement rate. Each one shows a slice of the picture. The yardstick below is the same for each: what data it sees, and where it stops.

Tool	What it shows	Suits	Where it stops
Google Postmaster Tools	Domain-level reputation, spam complaint rate and authentication results for mail sent to Gmail addresses	Senders with enough Gmail volume to appear in the dashboards	Covers Gmail only; shows nothing at low volume
Microsoft SNDS	Data on sending IPs delivering to Outlook.com consumer mailboxes	Senders who control or know their sending IPs	IP-based, consumer Outlook.com only
Seed-list testers such as GlockApps	Where a test message lands across a set of test inboxes	Checking a new domain, template or DNS change before sending	Test inboxes don't behave like real recipients
Brevo statistics	Delivered, soft and hard bounces, complaints and unsubscribes per campaign	Day-to-day delivery and bounce monitoring	Reports acceptance, not inbox versus spam

How EmailFlow OS sends: your Brevo account, your domain

This section describes a EmailFlow OS product, not one of the options compared above. With EmailFlow OS you record one video and upload it, connect your own Brevo account and sending domain, and import your prospect list into EmailFlow OS. EmailFlow OS then creates a personalised version of that recording for each recipient, not each company, and sends every version from your own inbox, through your Brevo account and your domain. Nothing goes out through a shared platform sender.

That matters for the numbers in this article. Your delivery, bounce and complaint figures sit in your own Brevo account, the reputation you build attaches to your own domain, and the SPF, DKIM and DMARC records are yours to manage. Whether a given message reaches the inbox is still decided by the receiving server, so the authentication, list hygiene and ramp-up steps above still apply. The features page explains how per-recipient personalisation and sending work.

Sales follow-up emails and your deliverability rate

Sales follow up email template

A sales follow-up email template that's safe for deliverability is short, plain text and sent as a reply in the original thread: "Hi {first name}, following up on my note from {day} about {topic}. Is this worth a short call, or should I close the loop? {Your name}". Replying in the thread keeps the In-Reply-To header, so the follow-up stays grouped with the first message. Swap the placeholders with real context. Identical follow-ups sent to hundreds of people give filters a pattern to match. You'll find eight variations in our sales follow up email template examples.

When should a follow up sales email not be sent?

Don't send a follow-up sales email to an address that hard-bounced, to anyone who unsubscribed, or to anyone who replied asking you to stop. Each of those adds a bounce or a complaint to your domain's record. A soft bounce on the first message is worth looking at before the next step goes out, since a full or disabled mailbox will usually bounce again.

Does a sales follow up email count against deliverability?

Yes. Every sales follow-up email is a separate send in your delivery rate and complaint numbers. A multi-step sequence to a bad list produces a new round of bounces at every step. Clean the list before the first touch, not between steps, and cap the sequence so that people who aren't responding stop getting mail. Open counts won't tell you when to stop either; our piece on email open rate tracking limits explains why pixel-based opens mislead cold senders.

Questions people ask

? Is a 25% email open rate good?

An open rate doesn't tell you much about deliverability. Opens are counted with a tracking pixel. Apple Mail Privacy Protection preloads that pixel, which inflates opens, and clients that block images undercount them. A seemingly healthy open rate can come from a list that is mostly landing in spam. Judge deliverability by bounces, complaints, seed tests and replies instead.

? Does a high delivery rate mean my emails reach the inbox?

No. Even a delivery rate in the 98–99% range that Mailjet calls healthy only means the receiving servers accepted those messages. Accepted messages can still be filed as spam, and the delivery rate counts them the same way. Inbox placement is a separate measure that you can only estimate, using seed-list tests and provider dashboards such as Google Postmaster Tools.

? What is the difference between a hard bounce and a soft bounce?

A hard bounce is a permanent rejection: usually the address doesn't exist or the receiving server refused the message outright. A soft bounce is a temporary failure, such as a full mailbox or a server that's unavailable, and the sending server retries it. Remove hard bounces immediately. Treat soft bounces that repeat across sends as hard ones.

? Can I see inbox placement in my Brevo account?

Brevo reports delivery events: delivered, soft and hard bounces, complaints and unsubscribes. Those cover acceptance by the receiving server, not which folder the message went to. To estimate inbox versus spam placement, add a seed-list test before a send and check Google Postmaster Tools for mail going to Gmail addresses.