Unique opens

Number of times a mailing has been opened, counting only one for each recipient. This figure can never be higher than the number of contacts in the list and is usually lower than the total number of opens because it does not count more than one per subscriber.

Do you want to know the real performance of your email campaigns? With Acrelia you have detailed statistics in real time. Try it now!

Why are unique opens important?

Unique opens let you know how many recipients have opened your email at least once. This metric is key to assessing the effectiveness of the subject line, the time of sending and the relevance of the sender. Unlike total opens, which can be overestimated with users who open the same email multiple times, unique opens give you a truer picture of initial reach.

What factors influence the unique open rate?

The subject of the message, which should arouse interest without appearing spammy.
The reputation of the sender, including the sender's name and email address.
The timing of the mailing, as not all days and times perform equally well.
The cleanliness of the database, to avoid inactive recipients. Even small variations in these elements can significantly influence the open rate.

How to improve this metric without falling into misleading practices?

Try short and personalised subject lines, avoiding excessive use of capital letters or emojis.
Perform A/B tests with different subject lines and sender names.
Segment your lists well so that the content is more relevant from the first glance.
Send at the times when your audience usually checks their email, adjusting for past behaviour.

The key is to generate genuine interest from the first impact.

What are the limits of this metric?

Unique opens are dependent on an invisible image being loaded as part of the email, which implies several limitations:

If the user blocks the loading of images, the open is not recorded.
Some mail clients automatically open messages, generating false positives.
New privacy policies, such as Apple's Mail Privacy Protection, may alter the data.

It is therefore advisable to combine this metric with others such as click-through rate or conversion, to get a more complete picture of campaign performance.