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Email Open Rate (EOR)


What is Email Open Rate?

Email Open Rate (EOR) measures the percentage of recipients that open a sent email.

How is Email Open Rate (EOR) used?

This metric reveals the initial impact of an email campaign and hints at subject line quality, sender deliverability, and an email's relevance to an audience. It's useful for measuring interest in product updates and as an early signal for A/B testing different email strategies.

How to calculate Email Open Rate (EOR)

Number of Emails Opened / Number of Emails Delivered x 100

To calculate EOR, divide the number of emails opened by the number of emails delivered, then multiply the result by 100.

Best Practices

Segment data to identify patterns across different audiences and content types. Attention to factors like send time optimisation and mobile-friendliness can improve EOR. Take technicals steps, such as setting up DMARC and SPF, to increase deliverability and open rates. The ROI in increasing EOR can be significant – a 50% increase in EOR could increase outbound sales revenue by 50%.

Common Misconceptions

EOR shouldn't be considered in isolation. While it indicates engagement, it's important not to overlook metrics like Click-Through Rate (CTR) and Conversions, which are better gauges of whether a campaign resonates with an audience.




What are the main drivers of Email Open Rate (EOR)?
  • Subject line effectiveness
  • Content quality
  • Content relevance
  • Domain reputation
How should I break down Email Open Rate (EOR)?
  • Campaign
  • Customer journey stage (if applicable)
  • Send time of day
  • Industry vertical
  • Company size

Supported Integrations

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