Summary
Google calculates spam rate as the percentage of emails marked as spam by users compared to the number of emails sent to the inbox. Experts suggest this calculation isn't fully transparent, and the accuracy of Google's FAQ is debated. The definition of 'active users' in Google Postmaster Tools is undefined, possibly encompassing recent Gmail engagement. User complaints significantly impact sender reputation. A low spam rate (below 0.1%) is vital. Key factors influencing spam rate are irrelevant content, poor list hygiene, and lack of authentication. Improving deliverability requires list hygiene, relevant content, sender authentication (SPF, DKIM, DMARC), engagement tactics, double opt-ins and monitoring feedback loops and user complaints.
Key findings
- Spam Rate Calculation: Google calculates spam rate as the percentage of emails marked as spam by users divided by the number of emails sent to the inbox.
- Active User Definition: The definition of 'active users' within Google Postmaster Tools remains undefined, but is speculated to refer to recent users who have been active in their accounts (logins etc).
- Complaints Impact: User complaints and direct spam marking are primary determinants of inbox placement and significantly impacts sender reputation.
- Spam Rate Threshold: Maintaining a spam rate below 0.1% is generally considered essential for good email deliverability.
- Sophisticated Spam Filtering: Google's spam filter uses sophisticated algorithms and considers various factors including individual user preferences.
Key considerations
- List Hygiene: Routinely clean your email lists by removing inactive or invalid addresses to improve engagement metrics.
- Content Relevance: Ensure email content is relevant, personalized, and engaging to reduce the likelihood of being marked as spam and to maximize opens and clicks.
- Sender Authentication: Implement and maintain SPF, DKIM, and DMARC authentication protocols to verify your sending identity and increase trust with mailbox providers.
- Double Opt-In: Implement a double opt-in process to verify email addresses and ensure that subscribers genuinely want to receive your emails.
- Engagement Tracking: Monitor engagement metrics such as open rates, click-through rates, and bounce rates to identify and address any deliverability issues or content performance problems.
- Feedback Loops: Implement and monitor feedback loops to identify and address user complaints and improve email practices, resolving deliverability issues.
What email marketers say
11 marketer opinions
Google calculates spam rate based on user-marked spam versus emails sent to the inbox. The exact definition of 'active users' in Google Postmaster Tools is not explicitly defined, but likely refers to users who have recently engaged with their Gmail account. Maintaining a low spam rate (ideally below 0.1%) is crucial for deliverability. Factors influencing spam rate include irrelevant content, misleading subject lines, outdated lists, poor sending reputation and low user engagement. Effective strategies to improve deliverability and reduce spam rates include list hygiene, double opt-ins, segmented content, monitoring bounce rates, A/B testing, email authentication (SPF, DKIM, DMARC), and using confirmed opt-in.
Key opinions
- Spam Rate Calculation: Google calculates spam rate as the percentage of emails marked as spam by users compared to those delivered to the inbox.
- Active User Definition: The precise definition of 'active users' in Google Postmaster Tools is not publicly available, but it likely involves recent engagement with the Gmail account.
- Spam Rate Threshold: Maintaining a spam rate below 0.1% is generally considered essential for good email deliverability.
- Impact of User Action: User engagement and actions, like marking emails as spam or not engaging, significantly affect sender reputation and deliverability.
Key considerations
- List Hygiene: Regularly clean your email lists to remove inactive or invalid addresses.
- Content Relevance: Ensure your email content is relevant and engaging to your audience.
- Sender Authentication: Implement SPF, DKIM, and DMARC authentication protocols to verify your sending identity.
- User Engagement: Focus on improving user engagement through targeted content, A/B testing, and monitoring bounce rates.
- Double Opt-in: Using double opt-in helps to ensure subscribers are genuine and engaged.
- Complaint Monitoring: Track and address any user complaints through feedback loops.
Marketer view
Email marketer from Hunter.io discusses the importance of keeping spam rate low (under 0.08%) by employing strategies such as using a confirmed opt-in, sending relevant and useful emails as well as segmenting your recipient list.
11 Jun 2025 - Hunter.io
Marketer view
Email marketer from Zerobounce discusses how several factors will impact your spam rates including: Sending to unengaged recipients, a high bounce rate and poor sending reputation.
10 Dec 2021 - ZeroBounce
What the experts say
6 expert opinions
Experts agree that Google's exact spam rate calculation methods are not fully transparent and their official FAQ may be misleading. Google considers user complaints a major factor in determining inbox placement, and its spam filter is highly sophisticated, learning from individual user preferences. The definition of 'active users' within Google Postmaster Tools remains undefined but could encompass various engagement metrics.
Key opinions
- Calculation Transparency: Google's precise methodology for calculating spam rate is not publicly detailed.
- FAQ Accuracy: The accuracy of Google's spam rate FAQ has been questioned, particularly regarding emails delivered directly to spam folders.
- Active User Definition: Google has not defined what constitutes an 'active user' in the context of spam rate calculation; potential factors may include logins, email opens, and tab visits.
- Complaint Impact: User complaints are a primary determinant of inbox placement, significantly impacting sender reputation.
- Sophisticated Spam Filter: Google's spam filter uses sophisticated algorithms to analyze emails and adapts to individual user preferences.
Key considerations
- User Complaints: Minimize spam complaints as much as possible, as they heavily influence deliverability.
- Content Relevance: Ensure email content is relevant and engaging to reduce the likelihood of being marked as spam.
- Inferred engagement: While Google is not transparent on active users, aim to maximise the number of active and engaged customers as a best practice.
- Proactive Monitoring: Monitor deliverability metrics and sender reputation to identify and address potential issues proactively.
Expert view
Expert from Wordtothewise.com shares the spam filter is very sophisticated and looks at a huge number of factors. It's designed to learn what the user considers spam and to put similar messages into the spam folder.
22 Dec 2021 - Wordtothewise.com
Expert view
Expert from Email Geeks says Google's spam rate FAQ is wrong, especially the part about substantial emails delivered directly to spam folders. She explains that spam foldering changes the spam rate because ESPs calculate based on 'number delivered' and assume all mail goes to the inbox. Google calculates the rate based on the amount of mail in the inbox.
4 Sep 2021 - Email Geeks
What the documentation says
4 technical articles
According to official documentation, Google calculates spam rate by dividing the number of user-reported spam emails by the total number of emails delivered to inboxes. A high spam rate negatively impacts deliverability, and spam complaints are a major factor in determining sender reputation. While Google's documentation doesn't define 'active users,' it implies the calculation focuses on users receiving emails in their inbox. Feedback Loops (FBLs) are essential for senders to monitor and address spam complaints, maintaining a healthy sender reputation.
Key findings
- Spam Rate Calculation: Spam rate is calculated as (emails marked as spam) / (emails sent to inbox).
- Active User Definition (Implicit): Google's calculation appears to focus on users who receive emails in their inbox, though 'active users' remains undefined.
- Complaint Importance: Spam complaints are a key factor influencing sender reputation and deliverability.
- Feedback Loops: FBLs provide crucial data for senders to identify and mitigate issues affecting deliverability.
Key considerations
- Minimize Spam Complaints: Strive to reduce spam complaints to maintain a positive sender reputation.
- Monitor Deliverability: Track deliverability metrics to identify and address potential issues.
- Implement Feedback Loops: Utilize FBLs to gain insights into user complaints and improve email practices.
Technical article
Documentation from SendGrid explains that ISPs like Google use spam complaints as a major factor in determining sender reputation. A higher complaint rate leads to filtering or blocking.
13 Sep 2024 - SendGrid
Technical article
Documentation from SparkPost explains that Feedback Loops (FBLs) provide senders with data on spam complaints, allowing them to identify and address issues affecting deliverability. This helps in maintaining a healthy sender reputation.
23 Oct 2021 - SparkPost
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