What Is Open Rate?
Open rate is one of the primary metrics used to evaluate email campaign performance. It tells you what proportion of the people who received your email actually opened it. Most email platforms calculate open rate using a tracking pixel, a tiny invisible image embedded in each email. When the email is opened and images are loaded, the pixel fires and registers an open against the recipient's address.
For example, if you send a campaign to 10,000 subscribers and 800 of them deliver and are opened (unique opens), your open rate is 8% from delivered, or expressed against the number actually delivered after bounces are removed. Most platforms track unique opens rather than total opens to avoid inflating results when a single recipient opens the same email multiple times.
Open rate is primarily a measure of two things: the quality of your subject line, and the strength of your sender identity. Subscribers decide whether to open an email in seconds based on who sent it and what the subject line promises. A familiar sender name builds trust over time, while a strong subject line creates curiosity or communicates clear value. Both elements must work together for open rates to remain consistently high.
It is important to understand the limitations of open rate as a metric. Apple's Mail Privacy Protection, introduced in 2021 for iOS 15 users, pre-fetches email content including tracking pixels for subscribers who enable the feature. This records an open even when the email was never actually read. As a result, open rates for senders with a significant Apple Mail audience are often overstated. Marketers should treat open rate as a directional indicator rather than an exact measurement, and supplement it with click-to-open rate and conversion data for a complete picture of campaign performance.
South African email marketers sending to local audiences will encounter a mix of Gmail, Outlook, and Apple Mail users depending on their sector. B2B audiences in Johannesburg and Pretoria tend to use Outlook heavily, while consumer audiences are more likely to include significant Gmail and Apple Mail usage. Understanding your audience's inbox distribution helps interpret open rate data more accurately and set realistic benchmarks.
Open Rate In Practice
The scenario below is an illustrative example, not a Juicy Designs client result. The figures indicate the scale of effect that subject line and open rate work typically produces, so treat them as indicative rather than measured.
Picture a Cape Town travel agency that sends a monthly newsletter about local and international travel deals, with an average open rate over the past year of around 25%. If it sends a campaign with the subject line "Your next adventure is waiting", the open rate could plausibly drop to something closer to 18%. If it then tests a subject line that names a specific destination and discount, such as "Mozambique from R3,200 return this October", the open rate might rise into the mid-30s. The specificity and relevance of the second subject line makes the decision to open immediately obvious for subscribers who have an interest in African travel.
This example illustrates the direct relationship between subject line quality and open rate. Vague, generic subject lines produce lower open rates because they give subscribers no compelling reason to open immediately. Specific, curiosity-driven, or value-communicating subject lines consistently outperform. For South African businesses, incorporating local context such as rand pricing, local destinations, or references to South African events can significantly increase relevance and drive higher open rates with local audiences than generic international-style copy.
Why open rate is no longer a reliable metric
Open rate is tracked by a small invisible image loading when the message is displayed. Two changes broke that mechanism.
Privacy protection features pre-load images for many recipients regardless of whether the message was read, which inflates opens. Meanwhile, recipients who read with images disabled register no open at all, which deflates them. The result is a number that is simultaneously overstated and incomplete, and not comparable to your own historical figures from before those changes.
Open rate retains some diagnostic value for relative comparison within a single campaign, such as subject line A versus B sent at the same time to the same list. It is close to useless as an absolute benchmark.
What to measure instead
| Metric | Why it is better |
|---|---|
| Click-through rate | Requires deliberate action, not affected by image pre-loading |
| Click-to-delivered rate | Removes list-size distortion |
| Replies | Strongest engagement signal, especially for B2B |
| Conversions from email | The only metric tied to revenue |
| Unsubscribe and complaint rate | Early warning on relevance and frequency |
If you report to a client or board that still expects open rate, keep it in the report but lead with clicks and conversions, and note once why the open figure is unreliable.
See click-through rate and email deliverability.
FAQ
What is a good open rate for email marketing?
A good email open rate varies by industry, but across most sectors an open rate between 20% and 35% is considered solid. B2B newsletters and highly segmented lists often achieve 35% or higher. Rates below 15% suggest problems with subject lines, sender reputation, list health, or relevance. Always compare your rates to your own historical benchmarks rather than broad industry averages.
Why did Apple's Mail Privacy Protection change open rate tracking?
Apple's Mail Privacy Protection, introduced in 2021, pre-fetches email content including tracking pixels for users who opt in, recording an open even if the recipient never looked at the email. This inflates open rates for senders with a large Apple Mail audience, making raw open rates less reliable as a precise metric. Using click-to-open rate and actual conversion data gives a more accurate picture of engagement.
What is a good email open rate?
Less meaningful than it used to be. Privacy features pre-load images and inflate opens for some recipients while others register none, so absolute benchmarks are unreliable. Compare within a single campaign and judge performance on clicks and conversions.
Should I stop tracking open rate entirely?
No, it remains useful for relative comparisons such as A/B testing subject lines on the same send. Just stop using it as a headline performance measure or comparing it to industry benchmarks.