Definition
Open rate is usually calculated as unique tracked opens divided by delivered messages. An open is inferred when a tiny remote image loads; it is not a direct record that a person read the email.
Image blocking can miss real reading, while Apple Mail Privacy Protection and other proxy systems can preload images without a person opening at that moment. The metric remains directional when compared carefully within similar audiences and environments.
Why it matters
Open trends can reveal large changes in sender recognition, subject performance, or estimated placement. They should not be used alone for automation, inactivity deletion, or campaign success.
How it works
- 01
The sender adds a unique tracking image URL.
- 02
An email client or privacy proxy requests that image.
- 03
The platform records the event and deduplicates unique recipients.
- 04
The count is divided by delivered messages and interpreted with known tracking limitations.
Example
Sent: 10,000
Bounced: 200
Delivered: 9,800
Unique opens: 3,136
Open rate: 3,136 ÷ 9,800 = 32.0%Common mistakes
- Calling a pixel load proof that a person read the message.
- Comparing unlike audiences or message types as if they were controlled tests.
- Removing subscribers based only on no recorded opens.
- Optimizing sender names or subjects for curiosity that harms conversion or complaints.
Key takeaways
- Open rate measures image requests, not human attention directly.
- Use it as a directional top-of-funnel signal.
- Pair it with clicks, replies, conversion, complaints, and customer activity.