What is Email Open Rate?

It reflects how many people opened your email compared to how many successfully received it (i.e., not bounced).

Formula:

Email Open Rate = (Unique Opens / Emails Delivered) × 100

This metric is tracked via an invisible pixel loaded when the recipient opens the email—though note: open rates can be inflated due to privacy features (like Apple Mail Privacy Protection) that auto-load images.

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Why It Matters in B2B SaaS

• Helps assess whether your subject lines resonate with your audience
• Signals sender reputation—low open rates can hurt deliverability
• Informs A/B testing strategies in lead nurture and product onboarding flows
• Indicates how well-segmented and engaged your lists are
• Provides early insight into campaign health before click or conversion data is available

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How to Measure Email Open Rate

1.Use your ESP (Email Service Provider)

• Platforms like HubSpot, Marketo, and Customer.io automatically track open rate
• View open rate per send, per segment, and over time

2.Account for deliverability

• Only measure opens against successfully delivered emails (exclude hard/soft bounces)

3.Segment by audience

• Analyze opens by persona, lifecycle stage, or behavior to uncover engagement patterns

4.Control for privacy impact

• Use clicks and downstream actions to validate open engagement, especially with Apple Mail-impacted lists

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Best Practices

• Test subject lines rigorously—keep them specific, relevant, and timely
• Personalize sender name (e.g., from a real person vs. brand)
• Send at optimal times—typically Tuesdays–Thursdays, late mornings or early afternoons in recipient’s time zone
• Clean your lists regularly—remove inactive or bounced addresses
• Warm up new domains and avoid spammy language to protect sender reputation