Summary
Achieving good email deliverability relies heavily on maintaining optimal benchmarks for key metrics, with the spam complaint rate being the most critical. Industry consensus emphasizes keeping complaint rates below 0.1%, with rates consistently exceeding this, particularly above 0.2-0.3%, signaling severe issues and potential blocking by mailbox providers. While open rates, typically ranging from 20% to 30%, and click-through rates, averaging 2% to 4%, are vital indicators of subscriber engagement and list health, they are not direct measures of inbox placement. The unique Click-to-Open Rate (CTOR) can provide more direct insights into engagement and deliverability. Ultimately, mailbox providers prioritize low complaint rates and positive engagement signals, making them essential for a healthy sender reputation and successful inbox placement.
Key findings
- Complaint Rate Thresholds: A spam complaint rate below 0.1% is consistently cited as crucial for strong deliverability and a healthy sender reputation by major mailbox providers and experts alike. Some even recommend aiming for 0.05% or lower, while rates above 0.2-0.3% are highly detrimental and can lead to significant deliverability issues.
- Open Rate Averages: Average email open rates typically range from 20% to 30% across industries, with some experts suggesting 15% as a minimum for reaching the inbox but needing better targeting, and 20% or higher as a good target for overall list health and deliverability indication.
- Click-Through Rate Averages: Average click-through rates (CTR) generally fall between 2% and 4%, though they can vary, with some industry-specific benchmarks reaching up to 6.5%. While important for engagement, CTR is not considered a direct deliverability metric.
- Mailbox Provider Focus: Mailbox providers (MBPs) primarily assess sender reputation and deliverability based on complaint rates and other engagement signals, generally not factoring in industry-specific benchmarks, except for sectors prone to fraud.
- Deliverability vs. Inbox Placement: Deliverability is a broad term encompassing technical and operational aspects, with the ultimate goal being inbox placement. Low complaint rates and healthy engagement metrics are key to achieving consistent inbox placement.
Key considerations
- Complaint Rate Focus: The spam complaint rate is the single most critical metric for email deliverability and sender reputation. Maintaining it well below 0.1%, ideally closer to 0.05%, is paramount, as rates consistently exceeding 0.1-0.2% can lead to severe deliverability issues, including throttling and blocking by mailbox providers.
- Open Rate as Engagement: While useful for gauging subscriber engagement and list health, open rates are not a direct indicator of inbox placement, as some experts note they do not reliably reflect whether emails are reaching the inbox. However, high engagement, signaled by good open rates, indirectly supports deliverability by reducing negative signals.
- Contextual Benchmarks: Benchmarks for open and click rates can vary significantly by industry, audience, and email type (e.g., promotional vs. transactional). Senders should compare their performance against their own historical data and relevant industry averages, rather than solely generic benchmarks.
- Click-to-Open Rate (CTOR): The unique Click-to-Open Rate (CTOR) can be a more telling metric for deliverability and subscriber engagement than raw open or click rates. A CTOR consistently under 10% may indicate problems and risk of blocks, whereas above 20% suggests strong engagement.
- IP Warming Thresholds: During IP warming, a unique open rate of 20% is considered a good step-up level indication. If performance falls below this, it may be advisable to hold or decrease sending volumes to avoid deliverability pitfalls.
What email marketers say
14 marketer opinions
Achieving and maintaining robust email deliverability fundamentally depends on adhering to stringent benchmarks for key engagement metrics, with the spam complaint rate standing out as the paramount indicator. Experts across the industry consistently advise keeping complaint rates below 0.1%, as anything higher can significantly jeopardize sender reputation and lead to email throttling or blocking. Open rates, typically between 20-30%, and click-through rates, generally 2-4%, reflect list health and subscriber engagement. While not direct deliverability metrics, strong performance in these areas provides positive signals to mailbox providers, thereby indirectly supporting inbox placement.
Key opinions
- Spam Complaint Rate Baseline: Across the board, an email spam complaint rate of under 0.1% is the critical benchmark for maintaining good deliverability and a healthy sender reputation. Many experts suggest aiming even lower, around 0.05%, with rates consistently above 0.1% or 0.2% posing significant risks of throttling and blocking by mailbox providers.
- Average Open Rate Range: Typical email open rates fall within the 20-30% range, though some industry averages can vary from 16% to 40%. While a 15% open rate might indicate inbox reach, rates consistently above 20% generally signify a healthy and engaged subscriber list.
- Average Click-Through Rate: Email click-through rates generally average between 2% and 4% across various industries, though specific sectors might see averages from 1.9% to 6.5%. This metric primarily reflects engagement rather than direct deliverability.
- Critical Role of Complaint Rate: The complaint rate is considered the most paramount direct deliverability metric, with some internet service providers (ISPs) beginning to throttle email volume at rates as low as 0.2%, irrespective of other engagement metrics.
- Mailbox Provider Evaluation Focus: Mailbox providers largely assess deliverability based on low complaint rates and positive engagement signals, generally not adjusting their algorithms for different industry benchmarks, except in sectors known for high fraud.
Key considerations
- Prioritize Complaint Rate Management: Focus efforts on keeping your spam complaint rate as low as possible, ideally below 0.05-0.1%, as this is the single most influential factor in your sender reputation and long-term deliverability success.
- Beyond Raw Engagement Metrics: While open and click rates are valuable indicators of list health and subscriber engagement, they are not direct measures of inbox placement. High engagement indirectly supports deliverability by signaling positive user interaction to mailbox providers.
- Leverage Click-to-Open Rate (CTOR): For a more insightful gauge of engagement relative to actual opens, monitor your unique Click-to-Open Rate (CTOR). A CTOR below 10% may indicate poor engagement and potential deliverability issues, while consistently above 20% suggests strong content and an engaged audience.
- Internal vs. Industry Benchmarks: While industry benchmarks provide context, prioritizing your own historical performance ('better or worse than yesterday') and understanding your unique audience's engagement patterns is crucial for sustainable deliverability improvements.
- Holistic Deliverability View: Understand that 'deliverability' is a broad concept encompassing technical setup, sender reputation, and audience engagement, with the ultimate goal being consistent 'inbox placement.' All metrics contribute to this holistic view.
Marketer view
Marketer from Email Geeks explains that for generic promotional email, an open rate of about 15% means you are likely getting to the inbox but need better targeting. He also notes that general performance should be 'better or worse than yesterday' for a quick benchmark.
5 Oct 2024 - Email Geeks
Marketer view
Marketer from Email Geeks considers below 0.1% to be a good target for spam complaints.
25 Oct 2024 - Email Geeks
What the experts say
4 expert opinions
Achieving and maintaining robust email deliverability fundamentally depends on adhering to stringent benchmarks for key engagement metrics, with the spam complaint rate standing out as the paramount indicator. Experts across the industry consistently advise keeping complaint rates below 0.1%, as anything higher can significantly jeopardize sender reputation and lead to email throttling or blocking. Open rates, typically between 20-30%, and click-through rates, generally 2-4%, reflect list health and subscriber engagement. While not direct deliverability metrics, strong performance in these areas provides positive signals to mailbox providers, thereby indirectly supporting inbox placement.
Key opinions
- Open Rate as a Deliverability Proxy: Some experts suggest maintaining above a 20% unique open rate as a benchmark for good deliverability and a strong indicator during IP warming to progressively increase sending volumes.
- Engagement vs. Deliverability Metrics: Both open rates and click-through rates are valuable for gauging subscriber engagement and interest, but neither is considered a direct metric for email deliverability or whether emails successfully reach the inbox.
- Complaint Rate Threshold: For optimal email deliverability, most Internet Service Providers (ISPs) consider a complaint rate of 0.1% (or 1 complaint per 1,000 messages) as the acceptable maximum threshold, with rates of 0.05% or lower being even more beneficial.
- Individual User Engagement: For individual users, a target of 1 in 5 email opens is considered good engagement, while a rate of 1 in 20 opens may indicate a lack of subscriber interest in your email program.
Key considerations
- Nuance of Open Rates: While a 20% open rate can be a useful internal target for engagement and as a step-up indicator during IP warming, it should not be solely relied upon as a direct measure of inbox placement, as some experts highlight it does not reliably reflect whether emails are reaching the inbox.
- Click Rates for Engagement: Click-through rates are primarily valuable for identifying highly engaged subscribers and optimizing content effectiveness, rather than serving as a direct assessment of email deliverability to the inbox.
- Complaint Rate is Paramount: Focus intensely on minimizing your spam complaint rate. Strive to stay well below the 0.1% threshold acceptable to most ISPs, with a rate of 0.05% or lower being highly advantageous for maintaining a strong sender reputation and ensuring consistent inbox placement.
- Strategic IP Warming: Utilize a 20% unique open rate as a key performance indicator during IP warming; if your volumes fall below this benchmark, consider holding or decreasing sending volumes to avoid negatively impacting your deliverability and sender reputation.
Expert view
Expert from Email Geeks suggests staying above a 20% open rate for good deliverability. He also advises that for individual users, 1 in 5 opens is a good target, while 1 in 20 indicates a potential lack of interest in the program. He reiterates that a 20% unique open rate (UOR) is a good step-up level indication during IP warming, recommending holding or decreasing volumes if below that.
29 Jun 2024 - Email Geeks
Expert view
Expert from Word to the Wise explains that open rates are not a reliable indicator for email deliverability. While useful for gauging subscriber engagement, they do not directly reflect whether emails are reaching the inbox.
23 Dec 2021 - Word to the Wise
What the documentation says
4 technical articles
Achieving and maintaining robust email deliverability fundamentally depends on adhering to stringent benchmarks for key engagement metrics, with the spam complaint rate standing out as the paramount indicator. Experts across the industry consistently advise keeping complaint rates below 0.1%, as anything higher can significantly jeopardize sender reputation and lead to email throttling or blocking. Open rates, typically between 20-30%, and click-through rates, generally 2-4%, reflect list health and subscriber engagement. While not direct deliverability metrics, strong performance in these areas provides positive signals to mailbox providers, thereby indirectly supporting inbox placement.
Key findings
- Critical Complaint Threshold: Leading email platforms like SendGrid and Campaign Monitor, along with major mailbox providers such as Google Postmaster Tools and Microsoft SNDS, consistently mandate a spam complaint rate below 0.1% as essential for strong deliverability and a healthy sender reputation.
- Problematic Complaint Rates: Spam complaint rates consistently above 0.2% to 0.3% are universally considered problematic, leading to significant deliverability issues, including the throttling or outright blocking of emails by providers like Gmail and Outlook.com.
- Average Engagement Benchmarks: Industry averages for email open rates are typically around 21.5%, and click-through rates generally hover around 2.3%.
- Impact on Specific Providers: High complaint rates directly impact deliverability to specific providers, with Google Postmaster Tools advising a strict sub-0.1% rate for Gmail and Microsoft SNDS indicating that rates above 0.1-0.2% will lead to issues with Outlook.com.
Key considerations
- Complaint Rate Paramount: The spam complaint rate is the most crucial metric for email deliverability; focus intently on keeping it below 0.1%, as rates exceeding 0.2-0.3% are highly detrimental and risk severe deliverability issues, including throttling and blocking by major mailbox providers.
- Monitor Mailbox Provider Guidelines: Adhere to the specific complaint rate thresholds advised by major mailbox providers like Google Postmaster Tools and Microsoft SNDS, as consistently exceeding their low benchmarks can result in direct penalties to your sender reputation and inbox placement.
- Engagement vs. Deliverability Role: Understand that while open rates (around 21.5%) and click-through rates (around 2.3%) are valuable indicators of subscriber engagement and content effectiveness, they are not direct deliverability metrics. Instead, they indirectly support deliverability by signaling positive user interaction to mailbox providers.
Technical article
Documentation from SendGrid highlights that maintaining a spam complaint rate below 0.1% is crucial for strong deliverability and a good sender reputation. They advise that rates exceeding 0.3% are highly detrimental and can lead to significant deliverability issues.
29 Nov 2021 - SendGrid
Technical article
Documentation from Campaign Monitor reports industry average open rates around 21.5% and click-through rates around 2.3%. For deliverability, they emphasize the importance of keeping complaint rates very low, ideally below 0.1% to 0.2%, to ensure consistent inbox placement.
19 May 2025 - Campaign Monitor
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