Open rate is the percentage of delivered emails that recipients open, calculated as unique opens divided by emails delivered. It is the most-cited email engagement metric, traditionally used to judge whether a subject line, sender name, and send time earned attention. In 2026, privacy changes have made it a directional signal rather than an exact count of human reads.
How is open rate calculated?
Open rate measures how many people opened an email out of everyone who received it. The standard formula is:
- Open rate = (unique opens / emails delivered) x 100
Two details matter. First, the denominator is emails delivered, not emails sent, so bounces are excluded. Second, most tools report unique opens (one open per recipient) rather than total opens, which would double-count a recipient who reopens the same message.
Opens are detected with a tiny invisible tracking pixel embedded in the email's HTML. When the recipient's mail client loads that image, the sending platform records an open. This is why open rate has always depended on whether images load, and why it has never been a perfect measure of a human actually reading the message.
A worked example makes the formula concrete. Say you send 1,000 emails and 40 bounce, leaving 960 delivered. If 230 unique recipients open the message, your open rate is 230 / 960, or about 24%. Notice that using the 1,000 figure as the denominator would understate the rate to 23% and reward you for a dirty list. Standardizing on delivered keeps the number comparable across sends of different sizes and list quality.
What is a good open rate in 2026?
A good open rate depends heavily on industry, audience, and how it is measured. Across providers, reported averages in 2025-2026 ranged widely: ActiveCampaign reported a roughly 39% average across its customer base, while Brevo reported about 20.7% excluding inflated Apple opens and 33.9% including them. The spread reflects measurement methodology as much as real engagement.
Rough industry benchmarks for 2026 look like this:
- Government, nonprofit, and education: 23-30%, the highest-engagement segments
- Ecommerce and retail: roughly 16-32% depending on list quality
- B2B services: commonly 15-22%
Treat any single number cautiously. The most useful benchmark is your own historical performance for comparable sends, not a published average from a different industry and a different measurement standard. For outbound work specifically, our cold email outreach use case covers how reply and meeting metrics anchor performance better than opens.
Why is open rate unreliable now?
Open rate accuracy collapsed after Apple Mail Privacy Protection (MPP) launched. MPP pre-fetches the tracking pixel when a message is delivered to Apple Mail, whether or not the recipient ever reads it. Every Apple Mail message is therefore logged as opened automatically.
By early 2025, Apple Mail accounted for roughly 58% of global email opens, meaning more than half of recorded opens can be machine-generated. Validity research found senders with Apple-heavy audiences saw reported open rates climb 18-32 percentage points above verified engagement, and the gap widened as iOS adoption grew. The practical takeaway: a rising open rate may reflect more Apple users on your list, not more interest.
Some platforms now filter suspected MPP and bot opens; others report the inflated number unchanged. Knowing which your tool does is essential before you compare any figure. There is also a second source of noise: security gateways and link-scanning services that fetch images and follow links to check for threats. These automated fetches can register both opens and, in some cases, clicks that no human ever made.
The combined effect is that two campaigns with identical reported open rates can have very different real engagement. A figure of 35% built mostly from Apple Mail pre-fetches is not comparable to 35% from a non-Apple audience whose opens are largely genuine. This is why year-over-year comparisons of raw open rate are misleading unless the underlying audience mix and the platform's filtering rules have stayed constant.
What metrics should replace open rate?
Because clicks require a deliberate action that MPP does not fake, click-based and downstream metrics are more trustworthy signals of real engagement.
- Click-through rate (CTR): clicks divided by delivered. Unaffected by pixel pre-fetching.
- Click-to-open rate (CTOR): useful only if your open data is clean, since it depends on opens.
- Reply rate: the clearest engagement signal for one-to-one and outbound email.
- Meetings booked and pipeline created: the outcomes that actually matter for outreach.
For teams running outreach, replies are the metric to optimize. Klovis tracks reply history per campaign and routes every response into a unified inbox across LinkedIn, email, WhatsApp, Instagram DM, and Telegram, so a reply is immediately attributed and ready to action rather than buried under inflated open counts.
A practical way to use the remaining open data is as a relative, same-audience test rather than an absolute benchmark. If you A/B test two subject lines against one segment on the same day, both variants face the same MPP inflation, so the difference between them still carries signal even if neither absolute number is trustworthy. The mistake is comparing your raw open rate to a competitor's published figure, or to your own number from a year ago, and drawing conclusions from a gap that is mostly measurement artifact.
How does open rate fit a multi-channel outreach strategy?
Open rate is an email-only metric. As outreach spreads across channels, leaning on it alone misses most of the picture. A prospect who ignores three emails but answers a LinkedIn message is fully engaged, yet your open rate would call that sequence a failure.
Klovis is a multi-channel outreach CRM. Campaigns run sequenced steps where each step declares its own channel and sends from your team's own connected accounts. Replies from every channel land in one unified inbox, feed a self-updating CRM of people and companies, and can be turned into deals. Event-triggered workflows act on real signals, such as a reply or a no-response, to advance prospects or book meetings.
In that model, open rate becomes one early diagnostic among many, not the scoreboard. See how Klovis stacks up against single-channel tools in our comparisons, or review plans on the pricing page.
Frequently asked questions
What is the difference between open rate and click rate?
Open rate measures how many delivered emails were opened; click rate measures how many recipients clicked a link inside. Click rate is more reliable today because clicks require deliberate human action, while opens can be triggered automatically by privacy features like Apple Mail Privacy Protection.
Why is my open rate over 50%?
An unusually high open rate is often a sign of inflation from Apple Mail Privacy Protection rather than exceptional engagement. If a large share of your list uses Apple Mail, those messages are logged as opened on delivery. Check whether your platform filters MPP opens before celebrating the number.
Is open rate still worth tracking?
Yes, but as a directional signal, not a precise truth. It remains useful for spotting big relative swings, comparing variations in an A/B test on the same audience, and monitoring deliverability trends. For judging real interest, prioritize clicks, replies, and meetings booked.
How can I improve open rate without gaming the metric?
Focus on list quality and relevance: keep your list clean, segment by interest, write clear and specific subject lines, send from a recognizable sender name, and test send times against the same audience. These improve genuine engagement, which shows up in clicks and replies even when open data is noisy.
Does open rate matter for cold outreach?
Less than for marketing newsletters. In outbound, reply rate and meetings booked are the metrics that map to results. Open rate can flag a weak subject line early, but a multi-channel sequence judged on replies gives a far more accurate read on whether your outreach is working.