Email open rates: what a good rate looks like and how to improve yours

What is email open rate and how is it measured?

Email open rate is the percentage of successfully delivered emails that were opened by recipients. The calculation divides the number of unique opens by the number of delivered emails and multiplies by 100. If 10,000 emails are delivered and 2,500 are opened, the open rate is 25%.

The mechanism behind this measurement is a tracking pixel: a tiny, invisible image embedded in the email. When a recipient opens the message and their email client loads images, the pixel fires and registers an open in the sending platform. This is how platforms including Mailchimp, Klaviyo, and HubSpot have traditionally tracked open events.

For a thorough understanding of all the metrics that matter alongside open rate, the email marketing analytics guide covers the full measurement picture including click-through rate, conversion rate, and revenue attribution.

Why Apple Mail Privacy Protection changed open rate data

In September 2021, Apple introduced Mail Privacy Protection (MPP) with iOS 15. When enabled, the feature pre-fetches email content including tracking pixels on Apple's servers before the user opens the message. This means the pixel fires regardless of whether the recipient actually reads the email.

The effect on open rate data has been substantial. Lists with a high proportion of Apple Mail users saw open rates jump by 10 to 20 percentage points overnight, not because more people were reading the emails but because Apple's servers were loading the tracking pixels. Mailchimp and Klaviyo now label these events separately as Apple Privacy Opens, allowing senders to see how much of their reported open rate is machine-generated rather than human-triggered.

The practical implication is that raw open rate numbers since late 2021 cannot be directly compared to figures from before that date, and lists with different proportions of Apple Mail users will show different degrees of inflation. A list that is 60% Apple Mail users will show much higher MPP-inflated opens than a list that is 15% Apple Mail users.

This does not make open rate useless. It does change how you use it. For tracking trends within your own list over time, open rate remains a reliable relative indicator. For comparing your performance against industry benchmarks or competitor data, the figure needs to be treated with caution.

What counts as a good email open rate by industry

Industry benchmarks for open rates are published by most major email platforms and typically show averages ranging from around 20% to over 40% depending on the sector. Non-profit organisations, government bodies, and educational institutions tend to sit at the higher end. Retail, travel, and entertainment typically sit lower.

These figures need context. Platform benchmark reports aggregate data from thousands of accounts with varying list qualities, audience types, and sending behaviours. A charity sending monthly updates to a small, opted-in supporter list is measured against e-commerce brands sending weekly promotional emails to large purchased audiences. The average conceals more than it reveals.

A more useful benchmark is your own historical performance. If your list has consistently produced open rates between 22% and 26% over the past 12 months and this month you see 18%, that drop is worth investigating regardless of what your industry average says. Conversely, if your platform-reported open rate has risen to 38% but you know your list skews heavily toward Apple Mail users, the rise may reflect MPP inflation rather than genuine improvement.

For broader context on where email performance figures sit across sectors, the article on email marketing benchmarks covers open rates, click rates, and conversion rates by industry with guidance on how to apply them to your own programme.

What actually drives email opens (beyond subject lines)

Subject lines get most of the attention when it comes to open rate optimisation, and they do matter. But they are one variable among several, and focusing exclusively on them while ignoring the others is a common mistake.

Sender name and trust

The sender name is the first thing most recipients see, appearing before the subject line in many inbox views. A familiar, trusted sender name outweighs a clever subject line for engaged subscribers. People open emails from people and brands they recognise. New subscribers have not yet built that familiarity, which is why welcome sequences typically produce higher open rates than cold lists receiving the same subject line.

Use a consistent sender name that matches how your audience knows you. Switching between a personal name, a brand name, and a departmental name (e.g. moving between "Sarah", "Sarah at Acme", and "Acme Marketing Team") fragments recognition and weakens trust over time.

List quality and engagement history

A list full of genuinely interested subscribers who opted in recently will produce higher open rates than a large list with many stale, disengaged contacts. List size does not determine open rate performance. List quality does.

Contacts who have not opened or clicked in 90 to 180 days actively drag your average open rate down and may be damaging your deliverability as inbox providers factor engagement rates into spam filtering decisions. Regular list hygiene, running re-engagement campaigns for cold subscribers before removing the non-responders, protects both your open rate and your ability to reach the inbox.

Deliverability and inbox placement

An email that lands in the spam folder or the promotions tab cannot be opened. Deliverability problems suppress open rates at the infrastructure level rather than the content level. If open rates drop sharply and suddenly rather than gradually, check your spam complaint rate, review recent sending behaviour for anything that might have triggered spam filters, and check your domain's sending reputation.

Platforms including Mailchimp and Klaviyo provide deliverability diagnostics within their reporting dashboards. For a deeper review of why deliverability affects open rate and how to address it, the guide on how to improve email open rates covers deliverability factors alongside subject line and content strategies.

Subject lines and preheaders

Subject lines set expectations and create the impulse to open. High-performing subject lines tend to be specific rather than vague, create curiosity or urgency without resorting to clickbait, and match the tone of the sender's established relationship with the list. A subject line that works well for a promotional brand email will often perform poorly for a personal-tone newsletter from an individual creator.

The preheader text, the short line visible after the subject line in the inbox preview, extends the subject line's selling power. Leaving preheader text blank wastes this space. Most platforms allow you to set custom preheader text separately from the email body, and treating it as a second subject line rather than a summary of the email's opening paragraph almost always improves performance.

Send timing and frequency

The day and time an email arrives affects whether it is noticed and opened. Most B2B lists perform better on weekday mornings, particularly Tuesday through Thursday. Consumer lists often show stronger performance on weekday evenings and weekend mornings, when recipients are browsing without work distractions. Neither pattern is universal, and the only reliable way to find the best timing for your specific list is to test it with your own audience.

Send frequency interacts with open rate in a compounding way. Sending too frequently trains subscribers to ignore your emails, producing gradual open rate decline over weeks and months. Sending too infrequently makes you unfamiliar to your list, so when you do send, recipients do not recognise you and are less likely to open. Finding the right cadence for your audience requires monitoring open rate trends alongside unsubscribe rate to identify when frequency is crossing into saturation.

How to improve your email open rate

Improving open rate is not a single action. It is the result of maintaining list quality, writing subject lines that earn the click, protecting deliverability, and sending to the right people at the right frequency. These factors work together, and neglecting one undermines the others.

Run consistent subject line tests

A/B testing subject lines is the most direct and measurable way to improve open rate. Most major platforms support subject line split testing natively. The standard approach sends version A to one segment and version B to another, typically 20% to 25% of your list for each variant, and then delivers the winner to the remainder after a set time period.

Test one variable at a time: length, question versus statement, personalisation, emoji presence, specific versus vague. Running tests where two variables change simultaneously makes it impossible to know which element drove the difference. Build a record of test results over time so you are drawing on accumulated evidence rather than running isolated experiments.

Maintain list hygiene regularly

Remove hard bounces immediately after each send. Run a re-engagement campaign to subscribers who have not opened or clicked in 90 days, offering them a clear reason to stay. Those who do not respond to the re-engagement campaign should be suppressed or removed rather than continuing to mail. A smaller, actively engaged list produces higher open rates, better deliverability, and more accurate analytics than a larger list with significant dead weight.

Segment before you send

Sending the same email to your entire list is rarely the optimal choice. Subscribers at different stages of the relationship with your brand, in different industries, or with different past purchasing behaviours have different reasons to open. Segmenting your list and customising subject lines and content for each segment typically lifts open rates more than any subject line test run against the full list. Klaviyo and HubSpot both offer powerful segmentation tools that make targeted sending manageable even for smaller teams.

Review your send time data

Most platforms show you the open time distribution for your campaigns: when recipients are actually reading your emails. Use this data to test different send times and compare open rates. If your list consistently shows peak opens at 8am on Tuesday but you are scheduling sends for Thursday afternoon, there is a straightforward improvement available without changing anything else in your email.

Track trends rather than individual campaigns

Open rate on a single campaign is a data point. Open rate across 20 campaigns is a trend. Build a consistent tracking record using Notion or a spreadsheet, recording each campaign's send date, audience size, subject line, open rate, and click rate. Trends reveal whether your programme is improving, whether certain campaign types consistently outperform others, and when something has changed in your list behaviour that warrants investigation.

What this means for how you measure email performance

Open rate matters, but it should occupy one position in a set of metrics rather than being the primary measure of email programme health. For measuring content quality, click-to-open rate is more reliable. For measuring commercial performance, conversion rate and revenue per email are cleaner indicators. For measuring list health, unsubscribe rate and engagement trends tell a more complete story.

The most productive use of open rate data is tracking your own trends, testing subject lines and sender configurations, and identifying when engagement is shifting before it becomes a deliverability problem. Comparing your open rate to industry averages without accounting for Apple Mail Privacy Protection, list composition, and platform differences produces a misleading picture.

For the full context on how email open rate sits within a broader analytics framework, the email marketing analytics guide covers the complete set of metrics, how they relate to each other, and how to use them to make better decisions about every campaign you send.