Open Rate
The percentage of people who open an email after receiving it. It's one of the most basic metrics for measuring whether your subject line and sender name actually get people to click. CMOs track it to understand email campaign performance and audience engagement.
Full Explanation
Open rate measures how many recipients actually open your email divided by how many you sent it to (minus bounces). Think of it like foot traffic into a physical store—you can send out 10,000 flyers, but open rate tells you how many people actually walked through the door.
Here's why this matters: your email subject line and sender name are your only sales pitch before someone decides to engage. Open rate is the first gate. If 20% of people open your email, 80% never see your message, no matter how brilliant the content inside. It's a leading indicator of whether your targeting, timing, and messaging are resonating.
In practice, you'll see open rate reported in every email marketing platform—Mailchimp, HubSpot, Klaviyo, Salesforce Marketing Cloud. It appears as a percentage next to each campaign. A 15% open rate might be average for B2B, while 25%+ is considered strong. The metric has nuance though: opens are tracked by whether recipients load images, so text-only readers or privacy-focused email clients may not register as opens.
For AI tools, open rate becomes important when evaluating subject line generation, send-time optimization, or audience segmentation features. If a vendor claims their AI improves open rates by 30%, you need to understand whether they're testing on your actual audience, what baseline they're comparing against, and whether the lift is statistically significant. Open rate is also a key input for AI models that predict which segments will engage—it's training data that helps algorithms learn what works.
Why It Matters
Open rate directly impacts ROI on email marketing spend. If your open rate drops 5 percentage points across a 500,000-person list, you're losing 25,000 potential conversions per campaign. Over a year of weekly sends, that's over 1 million lost touchpoints. For a B2B company with a $2M email marketing budget, a 5-point open rate improvement can translate to $200K-$400K in incremental pipeline.
When evaluating AI tools for email, open rate improvement is a concrete, measurable outcome to demand. Ask vendors for benchmarks: what's the average lift their subject line AI delivers? How do they measure it? Is it tested on your industry? Open rate is also a leading indicator of list health and audience relevance—declining open rates often signal that your segmentation or frequency strategy needs adjustment, which AI can help diagnose. Finally, platforms that combine open rate data with AI-driven insights (like predicting which segments will open) give you competitive advantage in real-time campaign optimization.
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Related Terms
Conversion Rate Optimization (CRO)
The practice of systematically testing and improving the percentage of website visitors who complete a desired action—like making a purchase, signing up, or downloading content. It's about making your existing traffic work harder, not just driving more traffic.
Click-Through Rate (CTR)
The percentage of people who see your ad or link and actually click on it. If 100 people see your ad and 5 click it, your CTR is 5%. It's one of the most basic measures of whether your message is compelling enough to get action.
Marketing Automation
Software that automatically executes repetitive marketing tasks—like sending emails, posting social content, or scoring leads—based on rules you set up. It saves your team time and ensures consistent follow-up with prospects at scale.
Email Deliverability
Email deliverability is the ability of your marketing emails to reach your subscribers' inboxes instead of being blocked, filtered, or marked as spam. It's the foundation of email marketing—if your emails don't arrive, no amount of creative copy matters.
Related Tools
Mailchimp's AI capabilities transform basic email marketing into predictive segmentation and content optimization, but integration remains clunky for enterprise workflows.
Native AI capabilities embedded directly into email workflows, reducing the need for external tools and manual segmentation work.
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Courses, workshops, frameworks, daily intelligence, and 6 proprietary tools — built for marketing leaders adopting AI.
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