What are average email deliverability rates across different mailbox providers?
Michael Ko
Co-founder & CEO, Suped
Published 19 Apr 2025
Updated 15 Aug 2025
5 min read
When we talk about email deliverability, it's easy to assume there's a single, universal rate that applies across the board. However, the reality is far more nuanced. What constitutes a good email deliverability rate can vary significantly depending on the mailbox provider receiving your emails. Each provider, from Gmail to Outlook and Yahoo, employs its own sophisticated set of filtering rules and reputation metrics.
This diversity in how emails are processed means that a campaign performing well with one provider might struggle with another. Understanding these differences is crucial for anyone involved in email marketing, as it helps in setting realistic expectations and identifying potential issues before they impact your overall success.
Monitoring your inbox placement across various mailbox providers is a fundamental step in optimizing your email program. It allows you to pinpoint where your emails are landing (inbox, spam, or even getting lost) and tailor your strategies accordingly. This proactive approach can significantly impact your campaign performance and sender reputation.
The underlying reasons for varied rates
Every mailbox provider (ISP or Internet Service Provider) has its own proprietary algorithms and anti-spam measures. These systems are constantly updated to combat new spamming techniques and provide the best experience for their users. Factors like content analysis, sender reputation, and user feedback signals all play a role in determining whether an email reaches the inbox.
This means your sender reputation, built on your historical sending behavior, complaint rates, and engagement, is evaluated uniquely by each provider. An email that passes Gmail's filters might still land in the spam folder at Outlook (formerly Hotmail or Live) or be blocked entirely by a corporate firewall.
General benchmarks and specific provider insights
While there's no single official source for all mailbox providers' average deliverability rates, various industry reports and testing services offer insights. Generally, the average email deliverability rate across all industries and providers hovers around 80-95%. However, this broad average can be misleading because some providers are more lenient than others, and specific industries or sending practices can skew results dramatically.
A 2024 study by EmailToolTester reported an average of 83.1% across 15 email service providers. Another report from Validity in 2023 indicated that approximately 84.8% of emails, on average, reached the intended inbox worldwide. These numbers highlight that a significant portion of emails still fail to land in the primary inbox.
For the major players like Gmail, Outlook, and Yahoo, the deliverability rates can fluctuate. While some reports suggest an average around 86% for these combined, specific results will always depend on the sender's practices. It's important to remember that these industry benchmarks are averages, and your individual performance could be higher or lower.
Below is a table showing generalized average inbox placement rates reported across various studies. These are indicative and can vary based on the specific testing methodology and time period.
Mailbox Provider
Average Inbox Placement Rate (approx.)
Notes
Gmail
85-90%
Strong focus on sender reputation and engagement.
Outlook/Hotmail
80-88%
Sensitive to spam complaints, often uses SBL (Spamhaus Block List).
Yahoo Mail / AOL
75-85%
Can be stricter for marketing emails, heavy reliance on engagement.
Other Providers (e.g., smaller ISPs, corporate domains)
Varies widely
Often use a combination of commercial and proprietary filters, potentially stricter.
Factors influencing inbox placement
Achieving high deliverability goes beyond just avoiding blacklists or blocklists. It hinges on a combination of technical configurations and content strategy.
Email authentication: Implementing SPF, DKIM, and DMARC is foundational for proving your legitimacy as a sender. While DMARC itself doesn't directly improve inbox placement, it helps establish trust and provides valuable feedback.
Content quality: Avoid spammy keywords, excessive images, or broken links. Personalization and relevant content can significantly improve engagement.
List hygiene: Regularly clean your email list to remove inactive or invalid addresses. Sending to spam traps or bouncing addresses can severely harm your sender reputation.
The importance of list hygiene
Maintaining a clean email list is paramount. High bounce rates signal to mailbox providers that your list is outdated or poorly sourced, leading to your emails being flagged as suspicious or even blocked. Regularly validating your list and removing unresponsive subscribers can dramatically boost your overall deliverability rates and protect your sender reputation.
Proactive steps to boost your rates
Improving your email deliverability is an ongoing process that requires constant vigilance. Start by consistently monitoring your email performance across different mailbox providers. This includes tracking inbox placement rates, open rates, click-through rates, and complaint rates. Tools that provide granular data can help you identify specific issues with certain providers.
Focus on building and maintaining a strong sender reputation. This means sending only to engaged subscribers, maintaining a consistent sending volume, and avoiding practices that trigger spam filters. Responding promptly to feedback loops and addressing any issues raised by mailbox providers (or users) can help improve your standing.
Effective strategies
Implement strong authentication: Ensure SPF, DKIM, and DMARC are correctly configured for your domain.
Segment your audience: Send targeted content to different groups to increase engagement.
Monitor blocklists: Regularly check if your IPs or domains are on any major blocklists and take action if listed.
Optimize content: Create valuable, relevant, and visually appealing emails.
Common pitfalls
Ignoring bounces: Not removing hard bounces from your list can damage your reputation.
Sending to unengaged users: Continuing to email inactive subscribers increases the risk of spam complaints.
Purchasing email lists: These lists often contain spam traps and unengaged contacts.
Content and volume errors
Sudden volume spikes: Rapidly increasing sending volume without warming up can trigger spam filters.
Generic content: Irrelevant or untargeted content leads to lower engagement and higher spam complaints.
Views from the trenches
Best practices
Regularly monitor your email deliverability rates across all major mailbox providers to catch issues early.
Segment your email lists and personalize content to increase engagement and reduce spam complaints.
Maintain strict list hygiene by removing inactive subscribers and hard bounces consistently.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly implemented and monitored.
Common pitfalls
Failing to monitor feedback loops from mailbox providers, missing crucial signals of deliverability issues.
Sending emails to unengaged segments of your list, which can lead to low open rates and high complaint rates.
Ignoring bounce reports, especially hard bounces, which indicate invalid email addresses and harm sender reputation.
Making significant changes to email volume or content without proper warm-up or testing periods.
Expert tips
An expert in email deliverability shared that if an email program is poorly managed, inbox placement can drop below 70%, even if the average is much higher.
A seasoned marketer pointed out that industry benchmarks are good starting points, but individual performance can deviate significantly based on specific audience engagement.
An email specialist noted that even if a mailbox provider has a small footprint, it's still worth understanding their filtering mechanisms if your audience uses them.
A deliverability expert suggested that authenticating emails with SPF, DKIM, and DMARC is fundamental, but DMARC's primary role is policy enforcement and reporting, not direct inbox placement improvement.
Expert view
Expert from Email Geeks says GlockApps publishes useful infographics on their users' average inbox, spam, and missing rates for various mailbox providers, which can serve as benchmarks for comparison.
February 18, 2021 - Email Geeks
Expert view
Expert from Email Geeks says it's important to clarify whether data from testing tools represents providers sending or receiving mail, though it's typically about receiving performance.
February 18, 2021 - Email Geeks
Navigating email deliverability
Email deliverability is a dynamic and complex field, heavily influenced by the distinct rules and preferences of each mailbox provider. While general averages provide a useful starting point, your actual success depends on how well you adapt your sending practices to these varied environments. By prioritizing strong authentication, engaging content, and diligent list hygiene, you can significantly improve your chances of consistently reaching the inbox, regardless of the recipient's provider. Continuous monitoring and strategic adjustments are key to navigating the intricacies of email deliverability.
Gmail to 
Outlook and Yahoo, employs its own sophisticated set of filtering rules and reputation metrics.
