What is an Email Open Rate?
Definition
Email open rate is a metric calculated as the percentage of recipients who open an email out of the total number of successfully delivered emails. For example, if you send 100 emails and 30 are opened by the recipient, your open rate would be 30%. Sales and Marketing teams reference open rates, as they provide the first indication of the performance and effectiveness of an outreach campaign. A high open rate suggests your subject line and pre-header text are compelling, and your list segmentation and send time are optimized.Recent Updates
The accuracy of open rates has become less reliable due to recent privacy changes and technological advances by major email service providers (ESPs).- Apple Mail Privacy Protection (MPP): This feature, introduced by Apple, pre-loads (prefetches) email content, including the tracking pixel used to log an open, before the recipient physically opens the email. This activity is logged as an “open” even if the recipient never actually views the message.
- Gmail and other ESPs: Similar prefetching, security scanning, and anti-spam activities by other services can also trigger the open tracking pixel without direct human action.
How Reevo Calculates Open Rates
Reevo has recently updated its open rate calculation methodology to ensure the most relevant and comparable data for our customers:| Period | Open rate definition | Rationale and Impact |
|---|---|---|
| Before November 19, 2025 | Excluded email opens within the first minute of send | Proxy to identify human engagement by filtering out rapid open activity typical of machine-driven behavior (e.g., prefetching). This may have excluded human-driven opens and artificially discounted the open rate. |
| Now (as of November 19, 2025) | Includes all email opens, regardless of timing | Provide a more relevant comparison with other email sales and marketing services, which typically include all activity |