Open rate: definition, calculation, and best practices to improve your email campaigns

What is the open rate?

Defining the open rate

The open rate is the percentage of recipients who opened an email out of those who actually received it. It is one of the classic email marketing metrics, used to gauge the appeal of a campaign in the minutes immediately following its delivery.

In practical terms, when a recipient opens an email, an invisible image (known as a tracking pixel) is loaded. It is this loading action that allows email platforms to record an open.

Therefore, the open rate does not measure actual content consumption. A person might open an email for a few seconds without reading it, and some opens may be triggered automatically by privacy protection systems.

Bon à savoir

Depuis l'introduction d'Apple Mail Privacy Protection, une partie des ouvertures est générée automatiquement, sans intervention de l'utilisateur. Les taux d'ouverture doivent donc être interprétés avec davantage de recul.

Why is this metric important for email marketing?

The open rate is an excellent indicator of the first impression your campaign makes.

Even before evaluating the quality of the content or the commercial performance of an email, it tells you whether recipients were interested enough to open it.

A low open rate can point to several issues:

• an unengaging subject line;
• a sender that doesn't inspire trust;
• poor deliverability;
• an outdated contact list;
• excessive sending frequency.

Conversely, a good open rate generally indicates that your message is reaching the right audience at the right time with a compelling promise.

For companies growing their acquisition through email or via a B2B lead generation agency, this metric is often the first signal used to evaluate the quality of a campaign before analyzing more advanced sales performance.

What is the purpose of the open rate in a marketing strategy?

The open rate is not an end in itself. It is a steering indicator that allows you to progressively optimize your campaigns.

It can be used, in particular, to:

• compare multiple email subject lines;
• identify the best times to send;
• measure the impact of a new segmentation;
• track changes in sender reputation;
• detect a decline in database quality.

Used over time, it helps you understand which practices actually improve performance.

For example, a company might find that systematically personalizing the subject line increases its open rate by several points, or that changing the sender name causes a sharp drop in results.

The goal is therefore not just to achieve a high number, but to identify the levers that sustainably influence email performance.

How do you calculate the open rate?

The calculation formula

The calculation is relatively simple.

Open rate = (Number of emails opened ÷ Number of emails delivered) × 100

It is important to use the number of emailsdeliveredand not the number of emails sent.

Rejected emails (hard bounces or soft bounces) should not be included in the calculation since they never reached the inbox.

Summary table

Difference between gross open rate and unique open rate

Not all platforms calculate open rates in the same way.

Two metrics are generally distinguished.

The unique open rate is usually the most relevant for measuring a campaign's ability to capture the audience's interest.

The gross rate, on the other hand, can provide insights into engagement when an email is viewed multiple times.

Example of open rate calculation

Let's look at a concrete example.

A company sends a campaign to5,000 contacts.

The results obtained are as follows:

• 5,000 emails sent;
• 4,850 emails delivered;
• 1,552 unique opens.

The calculation is therefore:

(1,552 ÷ 4,850) × 100 = 32%

The open rate is therefore32%.

This figure should then be compared:

• to previous campaigns;
• to industry averages;
• to other metrics such as click-through rate and conversion rate.

Bon à savoir

Une hausse du taux d'ouverture n'entraîne pas automatiquement une hausse des ventes. Un objet très attractif peut générer davantage d'ouvertures tout en produisant peu de clics si le contenu de l'email ne répond pas aux attentes créées.

What factors influence the open rate?

The open rate is rarely the result of a single element. Several factors combine to determine whether a recipient will decide—or not—to open your email.

Understanding these levers allows you to gradually optimize your campaigns without limiting yourself to just the subject line.

The email subject line

The subject line is the first thing visible in the inbox.

In just a few dozen characters, it must spark enough curiosity to encourage opening, without resorting to exaggerated promises.

The most effective subject lines are generally:

• clear;
• specific;
• benefit-oriented;
• tailored to the target audience.

Conversely, overly salesy phrasing, all caps, or excessive punctuation increase the risk of being ignored… or even flagged as spam.

The sender name

Even before reading the subject line, many recipients look at who is sending them the email.

An identifiable sender name inspires more trust than a generic address.

For example:

• Sophie Martin — Oliverlist
• Olivier from Oliverlist

will often perform better than:

• noreply@
• marketing@
• contact@

Consistency in the sender name also helps strengthen brand recognition across your campaigns.

The preheader

The preheader is the text that appears right after the subject line in most email clients.

It provides a second opportunity to convince the reader.

Rather than letting automatic text appear, such as"If you cannot view this email...", use this space to build on the promise made in the subject line.

The subject line and preheader should work together to spark curiosity while remaining consistent.

Email deliverability

Even the best subject line will yield no results if your emails never reach the inbox. Deliverability is therefore a prerequisite for a good open rate.

It depends on many criteria, including:

• the reputation of your sending domain;
• email authentication (SPF, DKIM, and DMARC);
• sending volume;
• spam complaint rate;
• bounce rate.

Email providers like Gmail, Outlook, or Yahoo assign a trust score to every sender. If this score drops, your campaigns risk being redirected to junk folders or even blocked entirely.

For companies that usecold email, maintaining an excellent sender reputation is essential to preserve long-term campaign performance.

Bon à savoir

Selon plusieurs études sectorielles, près d'un email commercial sur six n'atteint jamais la boîte de réception principale de son destinataire. Une bonne délivrabilité peut donc avoir davantage d'impact sur les résultats qu'une simple optimisation de l'objet.

Contact list quality

The performance of a campaign depends primarily on the quality of your database.

A recent, qualified, and regularly updated contact list naturally generates more opens than an aging database.

Conversely, several factors quickly degrade performance:

• obsolete addresses;
• contacts inactive for several years;
• generic email addresses (contact@, info@...) that are rarely checked;
• recipients who have never shown interest in your content.

This is also why purchasing email lists is strongly discouraged. These lists often contain unqualified or obsolete addresses, or spam traps that can permanently damage your sender reputation.

Timing of the send

Timing directly influences your open rate.

An excellent email sent at the wrong time can go completely unnoticed in a crowded inbox.

However, there is no universal "best" time.

The best time depends on several factors, including:

• your industry;
• your target audience profile;
• time zones;
• browsing habits.

In B2B, campaigns often perform well on weekdays, particularly in the early morning or late afternoon. However, some sectors see excellent results on Sunday evenings or very early Monday mornings.

The best approach is to test different sending times and analyze performance across several campaigns.

You can learn more about this in our guide onwhen to send a cold email, which details the most effective time slots for different sending contexts.

Audience segmentation

Sending the same message to your entire database is rarely the most effective strategy.

Segmentation involves tailoring campaigns based on specific criteria:

• industry;
• company size;
• job title;
• time in the database;
• interaction history;
• purchasing behavior.

The more relevant the content is to the recipient, the higher the chances of them opening it.

Take a SaaS provider as an example. A campaign aimed at sales managers will not use the same arguments as an email intended for SME executives.

This personalization improves not only the open rate, but also clicks and conversions.

What is a good open rate?

It is tempting to compare your open rate to a benchmark. However, there is no universal threshold.

Performance varies depending on the industry, the type of campaign, the quality of your contact list, and the sender's reputation.

The most relevant approach is to track your own results over time while comparing them to industry averages.

Averages by industry

Some sectors naturally benefit from higher open rates than others.

For example, non-profits or training organizations often have highly engaged audiences, while highly competitive sectors see more modest performance.

Table — Indicative averages by sector

These figures are just benchmarks. They can vary based on email platforms, data quality, or the impact of Apple Mail Privacy Protection.

Differences between B2B and B2C

B2B campaigns generally show higher open rates than B2C campaigns.

Several reasons explain this difference.

In B2B:

• lists are often smaller;
• messages are more targeted;
• recipients receive fewer sales solicitations than individual consumers;
• the needs expressed are often more specific.

In B2C, competition in the inbox is much fiercer.

Consumers can receive dozens of promotional emails every day, which mechanically reduces open rates.

This does not mean that a B2C campaign is less effective. The volumes sent and marketing objectives are often very different.

Factors explaining performance differences

Comparing only a percentage can lead to the wrong conclusions.

Two companies in the same sector can achieve very different results based on several criteria.

Key factors include:

A company that sends highly targeted campaigns to a qualified audience will generally achieve better results than a brand broadcasting the same message to tens of thousands of disengaged contacts.

Bon à savoir

Chercher à battre les moyennes du marché est rarement le meilleur objectif. Une progression régulière de vos propres performances est un indicateur bien plus pertinent qu'une comparaison avec des benchmarks génériques.

How can you improve your open rate?

Improving your open rate doesn't rely on a magic trick. The best performance usually results from a combination of best practices applied consistently.

The most successful companies continuously optimize their email subject lines, segmentation, sender reputation, and the quality of their contact list.

Writing more effective email subject lines

The subject line is the primary trigger for opening an email.

In just a few words, it must convince the recipient that your email is worth their attention.

The best subject lines prioritize clarity, relevance, and an explicit promise rather than intentionally mysterious phrasing.

Best practices

Subject lines that generate the best results often share several common characteristics:

• clearly state the benefit;
• keep it concise (40 to 60 characters);
• spark curiosity without being manipulative;
• use a natural tone;
• personalize only when it adds real value;
• avoid words associated with spam.

A few examples:

• How can you improve your open rate?
• Three mistakes that hurt your email campaigns
• Does your campaign deserve a second send?

Mistakes to avoid

Conversely, some subject lines significantly reduce performance:

• excessive use of capital letters;
• overuse of emojis;
• misleading promises;
• excessive punctuation ("!!!");
• subject lines that are too vague ("Important information").

When the subject line does not reflect the actual content of the email, recipients quickly lose trust, which degrades the performance of future campaigns.

Personalizing campaigns

Personalization is often reduced to adding a first name in the subject line or the body of the message. However, effective personalization goes much further.

The goal is to send an email that feels like it was designed specifically for the recipient. This requires a better understanding of your audience and the use of the data you have available.

You can personalize, for example:

• the industry;
• the contact's job title;
• company size;
• business challenges;
• the content offered;
• calls to action.

For example, a sales director and a marketing manager have different expectations. Tailoring your message to their specific context naturally increases the chances of opens, as well as clicks and conversions.

Personalization is particularly effective when it is based on aB2B lead generationstrategy, where each campaign addresses a specific identified issue rather than a target audience that is too broad.

Segmenting your database

Segmentation is one of the most powerful levers for improving your campaign performance.

It involves dividing your contacts into homogeneous groups in order to send more relevant messages.

The most commonly used segmentation criteria are:

• industry;
• company size;
• location;
• job title;
• sales maturity level;
• engagement with previous campaigns.

The more precise your segmentation, the more relevant your communication becomes.

Conversely, sending the same email to thousands of contacts with very different profiles generally leads to a gradual decline in opens and clicks.

Optimize sender reputation

Email providers constantly evaluate the reputation of the domains and addresses sending emails.

A poor reputation reduces the visibility of your campaigns, even if the content is high quality.

To maintain this reputation:

• gradually increase your sending volumes;
• avoid sudden spikes in campaigns;
• promptly remove invalid addresses;
• limit spam complaints;
• monitor your bounce rates;
• properly authenticate your domain.

Companies that industrialize their prospecting usingsales automationpay close attention to this reputation, as it directly determines campaign deliverability.

Regularly clean your contact database

A database naturally degrades over time.

Employees change companies, some addresses become inactive, and others no longer check the emails sent to them.

Regular cleaning helps to:

• reduce bounces;
• improve deliverability;
• maintain a good reputation;
• obtain more representative statistics.

It is recommended to identify contacts who have been completely inactive for several months and to implement re-engagement campaigns before deleting them.

This approach often improves overall performance without sending more emails.

Bon à savoir

Une base plus petite mais engagée produit généralement de meilleurs résultats qu'une base volumineuse composée de contacts inactifs. Les fournisseurs de messagerie tiennent compte de l'engagement des destinataires dans leurs algorithmes.

Testing with A/B Testing

A/B testing involves comparing two versions of the same email to identify which one performs best.

The most frequently tested elements are:

• the subject line;
• the sender name;
• the preheader;
• the time of sending;
• the day of sending.

To obtain reliable results, it is essential to change only one element at a time.

Example

After sending to a representative sample, the best-performing version is then sent to the rest of the list.

This method allows for the gradual improvement of results through data-driven decisions rather than intuition.

Mistakes that lower your open rate

Certain practices directly penalize email campaign performance.

Identifying them often leads to quick improvements in results.

Buying email lists

Purchasing an email database may seem like a quick way to grow your audience.

In reality, this practice generally leads to:

• low contact relevance;
• higher bounce rates;
• more spam reports;
• a damaged sender reputation.

The consequences can last for several weeks, or even months.

To understand the risks associated with this practice, check out our article onbuying email lists.

Sending campaigns too frequently

Sending frequency strongly influences recipient behavior.

Campaigns sent too close together often lead to:

• a drop in open rates;
• more unsubscribes;
• an increase in spam complaints.

Conversely, sending emails too infrequently can reduce brand recognition.

The goal is therefore to find a rhythm that aligns with your audience's expectations.

Using misleading subject lines

Deliberately sensationalist subject lines may generate more opens in the short term.

However, when the content does not match the promise made, the consequences are often negative:

• loss of trust;
• fewer clicks;
• increased unsubscribes;
• damaged reputation.

The subject line should spark curiosity without manipulating the reader.

Neglecting email authentication (SPF, DKIM, DMARC)

SPF, DKIM, and DMARC protocols allow email providers to verify that an email actually originates from the stated domain.

Without these mechanisms:

• more emails are marked as spam;
• some messages are rejected;
• your reputation may be harmed.

Today, these protocols have become essential for any serious email marketing strategy.

The limitations of open rates

For many years, the open rate was the benchmark metric for email campaigns.

Today, it must be interpreted with more caution.

Developments in privacy protection tools have profoundly changed how opens are tracked.

Why this metric has become less reliable

Historically, open tracking has relied on an invisible pixel that loads when the email is displayed.

However, some email providers now automatically download these images to protect user privacy.

The result:

• some opens are recorded even though the email was never read;
• it is becoming difficult to distinguish genuine interactions from automated opens.

The open rate therefore remains useful for tracking trends, but should no longer be interpreted as an exact measure of actual readership.

The impact of Apple Mail Privacy Protection (MPP)

Since iOS 15, Apple has offered theMail Privacy Protection (MPP)feature.

When enabled, Apple automatically downloads the images contained in emails, including the tracking pixel.

In practical terms, this means that:

• opens can be counted even if the user never viewed the message;
• some open rates appear artificially higher;
• comparisons between different audiences become more complex.

This development affects a significant portion of Apple users and explains why many platforms now recommend placing greater importance on clicks and conversions.

Why analyze other KPIs as well

The open rate remains an interesting indicator, but it is not enough on its own to evaluate the success of a campaign.

A comprehensive analysis relies on several complementary KPIs.

To go further, it is recommended to also trackprospecting KPIsin order to evaluate the actual performance of your campaigns, from the initial open to the generation of business opportunities.

The goal is no longer just to get opens, but to measure the real impact of your emails on your business.

Which metrics should you track alongside your open rate?

While the open rate is a good indicator of visibility, it is not enough on its own to evaluate the success of an email campaign.

To measure the true effectiveness of your emails, it is recommended to analyze several complementary KPIs. Together, they provide a much more precise view of your recipients' behavior and the performance of your strategy.

Click-Through Rate (CTR)

TheClick-Through Rate (CTR)measures the percentage of recipients who clicked on at least one link in your email.

Unlike the open rate, it reflects a concrete user action.

The formula is as follows:

CTR = (Number of clicks ÷ Number of delivered emails) × 100

A high open rate combined with a low CTR may reveal a disconnect between the promise of the subject line and the content of the email.

Conversely, a good CTR indicates that your message is generating genuine interest.

Click-To-Open Rate (CTOR)

TheClick-To-Open Rate (CTOR)measures the percentage of recipients who clicked after opening the email.

Its formula is as follows:

CTOR = (Number of clicks ÷ Number of opens) × 100

This metric allows you to evaluate the quality of your email content independently of the subject line.

A low CTOR may indicate:

• unconvincing content;
• a poorly visible call to action;
• poor information hierarchy;
• an offer that doesn't meet the expectations set by the subject line.

Conversion rate

The true goal of an email campaign isn't just to generate opens or clicks.

What really matters is the action taken after the click.

Depending on your goals, a conversion can be:

• booking an appointment;
• requesting a demo;
• downloading a white paper;
• signing up;
• making a purchase;
• creating an account.

The conversion rate is generally the most relevant metric for measuring the return on investment of your campaigns.

Bounce rate

The bounce rate corresponds to the percentage of emails that could not be delivered.

There are two categories:

A high bounce rate gradually damages your sending domain's reputation.

It is therefore essential to regularly remove invalid addresses from your contact list.

Unsubscribe rate

The unsubscribe rate measures the proportion of recipients who choose to stop receiving your emails.

A few unsubscribes are perfectly normal.

However, a sudden spike can indicate several issues:

• excessive sending frequency;
• poor targeting;
• irrelevant content;
• unmet expectations.

Monitoring this metric allows you to adjust your strategy before your domain reputation is impacted.

Bon à savoir

Une campagne peut afficher un excellent taux d'ouverture tout en générant un nombre important de désabonnements. C'est pourquoi il est essentiel d'analyser plusieurs KPI simultanément plutôt qu'un seul indicateur.

Tools for measuring open rates

Performance tracking is now integrated into the majority of email marketing solutions.

These platforms allow you to view opens, clicks, conversions, and many other metrics in real time.

Email marketing platforms

Email marketing solutions generally offer comprehensive dashboards to track:

• open rate;
• click-through rate;
• conversion rate;
• bounces;
• unsubscribes.

They also offer A/B testing, segmentation, and campaign automation features.

Marketing automation tools

Marketing automation platforms go beyond just sending emails.

They allow you to:

• create automated workflows;
• trigger campaigns based on user behavior;
• score leads;
• track their progress through the conversion funnel.

These tools make it easy to analyze the entire prospect journey, from opening an email to signing a contract.

CRM with performance tracking

Modern CRMs allow you to link email statistics to sales results.

This approach provides a much more relevant perspective than simply tracking open rates.

For example, you can measure:

• the number of opportunities created;
• appointments booked;
• sales generated;
• revenue attributable to campaigns.

For sales teams, this insight is essential to identify which actions actually drive results.

Conclusion

The open rate remains a key indicator for evaluating the visibility of your email campaigns. It allows you to quickly identify the impact of a subject line, sender, or segmentation on your campaign performance.

However, this KPI should no longer be analyzed in isolation. Developments in privacy protection technologies, such as Apple Mail Privacy Protection, now require a more nuanced interpretation of results. To effectively manage your strategy, it is essential to cross-reference the open rate with the click-through rate, CTOR, conversion rate, and other performance indicators.

By applying the best practices outlined in this guide—subject line refinement, segmentation, list cleaning, deliverability optimization, and A/B testing—you will have all the tools needed to sustainably improve your email campaigns and maximize their commercial impact.

Open Rate FAQ

How is the open rate calculated?

The open rate is calculated by dividing the number of emails opened by the number of emails delivered, then multiplying the result by 100.

Open Rate = (Emails Opened ÷ Emails Delivered) × 100

What is a good email open rate?

There is no universal benchmark.

As a general rule:

• a rate below20%may indicate issues with targeting or deliverability;
• between20% and 30%, performance is considered solid in many sectors;
• above30%, campaigns are often considered high-performing, especially in B2B.

The most important thing, however, is to compare your results against your own previous campaigns.

Why is my open rate low?

Several factors can explain a low open rate:

• an unappealing subject line ;
• a poor sender reputation ;
• an outdated contact list ;
• deliverability issues ;
• insufficient segmentation ;
• an unsuitable sending frequency.

Before modifying your campaigns, also verify that your emails are successfully reaching the inbox.

How can you quickly increase your open rate?

The quickest gains usually come from the following actions:

• reworking email subject lines ;
• improving the preheader ;
• further segmenting your audience ;
• cleaning your contact list ;
• testing different sending times ;
• conducting A/B tests.

However, long-term improvement relies on a comprehensive strategy rather than isolated optimizations.

Is the open rate still a reliable KPI?

The open rate remains useful for identifying trends and comparing multiple campaigns.

However, it has become less accurate since the introduction of Apple Mail Privacy Protection (MPP), which can record automatic opens without user intervention.

It is therefore recommended to supplement your analysis with the click-through rate, CTOR, and conversion rate.

What is the difference between open rate and click-through rate?

The open rate measures the number of recipients who opened the email.

The click-through rate measures the number of recipients who clicked on a link within that same email.

The former evaluates the appeal of your campaign, while the latter measures the actual engagement of your audience.