Email Open Rate: What It Is and How to Improve It

Open rate is the first metric most email senders look at, and for good reason. If people aren't opening your emails, nothing else matters — not your copy, not your links, not your offers. But open rate is also one of the most misunderstood metrics in email. Let's set the record straight.

What Is Email Open Rate?

Email open rate is the percentage of delivered emails that were opened by recipients. The formula is straightforward:

Open Rate = (Unique Opens / Delivered Emails) x 100

Note the word "delivered" — not "sent." Bounced emails are excluded from the calculation because they never had a chance of being opened. If you sent 1,000 emails, 50 bounced, and 285 were opened, your open rate is 285 / 950 = 30%.

As we covered in our guide to email tracking, opens are detected through a tracking pixel — a tiny transparent image that fires a request when the email is rendered. This method has known limitations, which we'll address below.

What Is a Good Open Rate?

The honest answer: it depends. Industry benchmarks vary significantly, but here are some general ranges based on aggregate data from major email platforms:

• SaaS / Technology: 20-28%
• E-commerce: 15-22%
• Media / Publishing: 22-30%
• Professional Services: 18-25%
• Nonprofits: 25-35%
• Transactional emails: 60-80%

Transactional emails (order confirmations, password resets) naturally have the highest open rates because recipients are expecting them. Marketing emails and newsletters sit lower because they compete for attention in crowded inboxes.

Rather than obsessing over absolute numbers, focus on your own trend line. A consistent 22% open rate that holds steady is better than a 35% that's declining month over month.

Why Your Open Rate Might Be Inaccurate

Before you optimize, it's worth understanding why open rate is an imperfect metric:

False negatives: undetected opens

Some email clients block images by default (especially Outlook in corporate environments). If a recipient reads your email but images don't load, the tracking pixel never fires. Your email was opened, but you don't know about it.

False positives: inflated opens

Apple's Mail Privacy Protection (MPP), introduced in iOS 15, pre-fetches email content through Apple's servers. This means every email sent to an Apple Mail user appears as "opened," even if they never actually read it. Security scanners in enterprise email systems can also trigger false opens.

These factors mean your true open rate is somewhere between your reported number and reality. The reported number is still useful for tracking trends — just don't treat it as gospel truth.

Proven Strategies to Improve Your Open Rate

1. Write Subject Lines That Earn the Click

Your subject line is the single biggest factor in whether someone opens your email. A few principles that consistently work:

• Be specific. "Your Q3 report is ready" beats "Check this out"
• Create genuine curiosity. "The metric 73% of senders ignore" makes you want to know which one
• Keep it short. 40-60 characters is the sweet spot. Mobile devices truncate longer subjects
• Avoid spam triggers. ALL CAPS, excessive exclamation marks, and words like "FREE!!!" trigger spam filters and reduce trust
• Use the preview text. The preview text (preheader) is your subject line's wingman. Use it to add context, not just repeat the subject

2. Optimize Your Send Time

There's no universal "best time to send." It depends entirely on your audience. A B2B SaaS newsletter might perform best at 9 AM on Tuesday, while a D2C brand might see higher engagement on Saturday mornings.

With Mailpulse analytics, you can see exactly when your emails get opened. Look at the hourly distribution of opens across your last several campaigns. You'll likely spot a pattern — a time window where most of your recipients are actively checking email.

3. Segment Your Audience

Sending the same email to everyone on your list is a guaranteed way to see mediocre open rates. Different segments of your audience care about different things.

Basic segmentation approaches that make a real difference:

• By engagement level: active openers vs. inactive subscribers
• By behavior: people who clicked product links vs. those who read blog content
• By source: subscribers from your website vs. event attendees

4. Clean Your List Regularly

Dead email addresses drag your open rate down and hurt your sender reputation. If someone hasn't opened any of your last 10 emails, they're either not interested or the address is abandoned.

Run a re-engagement campaign for inactive subscribers. If they still don't respond, remove them. A smaller, engaged list always outperforms a large, disengaged one.

5. Authenticate Your Sending Domain

Emails from unauthenticated domains are more likely to land in spam. Make sure you have SPF, DKIM, and DMARC records properly configured. If you're using custom tracking domains, these should align with your sending domain for maximum deliverability.

6. Be Consistent

If you send a newsletter every Tuesday and suddenly go silent for three weeks, your next email will perform poorly. Recipients forget who you are. Spam filters also look favorably on consistent sending patterns.

Pick a cadence and stick to it. Weekly, biweekly, monthly — whatever works for your content volume. Consistency builds habit, and habit drives opens.

Tracking Your Open Rate Over Time

The real power of open rate data comes from watching it over time. With a tool like Mailpulse, you can track open rates per campaign and see how changes to your subject lines, send times, or content affect engagement.

Set up a plan that matches your volume and start building your baseline. After 4-6 campaigns, you'll have enough data to make informed decisions about what works for your specific audience.

Open rate is just one piece of the puzzle. For a complete picture, you'll also want to monitor your click-through rate and the other key metrics every sender should track.