Inbox Placement Rate
The percentage of sent emails that successfully land in the recipient's primary inbox rather than spam, promotions, or junk folders.
Inbox placement rate (IPR) measures the percentage of your emails that actually reach the recipient's inbox — not just their server (which is what delivery rate measures). An email can be "delivered" (accepted by the server) but still end up in the spam or junk folder, which is why inbox placement rate is a more meaningful metric than delivery rate.
The difference between delivery rate and inbox placement rate:
- Delivery rate: (Emails accepted by server / Emails sent) × 100. A 98% delivery rate sounds great, but it doesn't tell you where the email landed.
- Inbox placement rate: (Emails in inbox / Emails sent) × 100. This is the true measure of deliverability. Industry average is 80-85%; top senders achieve 95%+.
Factors that affect inbox placement:
- Sender reputation (IP and domain)
- Email authentication (SPF, DKIM, DMARC)
- Content quality and spam score
- List hygiene and engagement rates
- Sending consistency and volume patterns
- Recipient engagement history with your emails
How to measure inbox placement: Tools like GlockApps, Everest (Validity), and InboxMonitor use seed lists — test email addresses at major ISPs — to measure where your emails actually land. SendSure's deliverability testing evaluates the infrastructure factors (authentication, blacklists, DNS configuration) that determine inbox placement.
Related Terms
Sender Reputation
A score assigned by ISPs to your email sending domain/IP that determines whether your emails reach the inbox.
Email Authentication
The umbrella term for protocols (SPF, DKIM, DMARC) that verify a sender's identity and prevent email spoofing.
Spam Score
A numerical rating that predicts how likely an email is to be classified as spam by ISP filters.
Engagement Rate
The percentage of email recipients who interact with your emails through opens, clicks, replies, or forwards.
Want to learn more?
Read our in-depth blog posts on email verification and deliverability.