Open rate vs click rate

This guide explains how open rate and click rate are defined, calculated, and interpreted in Sender, and how these two metrics relate to each other when evaluating email performance.

What these metrics measure

Open rate measures the percentage of delivered emails that were opened by recipients. It indicates whether your subject line, sender name, and send timing were effective enough to prompt recipients to view your email. Click rate measures the percentage of delivered emails that received at least one link click. It indicates whether your email content, calls to action, and link placement were compelling enough to drive recipient interaction beyond simply opening the message.

Together, these two metrics represent two distinct stages of email engagement — initial attention (open) and active response (click).

Metric definitions

Open rate — Calculated as the number of unique opens divided by the number of delivered emails, expressed as a percentage. This metric appears as opened in the Statistics section of the Campaign overview page, displayed as a percentage with the unique open count in parentheses. It is also shown as opens (percentage) in the Automations list and as Total opens (count) on the Dashboard under Traffic and reach report.

Click rate — Calculated as the number of unique clicks divided by the number of delivered emails, expressed as a percentage. This metric appears as unique clicks in the Statistics section of the Campaign overview page, displayed as a percentage with the unique click count in parentheses. It is also shown as clicks (percentage) in the Automations list and as Total clicks (count) on the Dashboard under Traffic and reach report.

Click-to-open rate (CTOR) — Calculated as the number of unique clicks divided by the number of unique opens, expressed as a percentage. While Sender does not display CTOR as a standalone metric card, you can derive it from the opened and unique clicks values shown in the Statistics section of any Campaign overview page. CTOR isolates content engagement among recipients who already opened the email.

How to interpret the data

Open rate between 15–25% — Generally considered a healthy range for marketing emails, though benchmarks vary significantly by industry, list size, and audience type. Rates in this range suggest that your subject lines and sender reputation are performing adequately.

Open rate below 10% — May indicate subject line issues, poor sender reputation, list fatigue, or deliverability problems where emails are landing in spam folders rather than the inbox. Investigate whether your hard bounced or soft bounced rates in the Statistics section are elevated, as delivery failures reduce the denominator and can mask the underlying engagement problem.

Open rate above 40% — Unusually high open rates may reflect a highly engaged niche audience, or they may be inflated by Apple Mail Privacy Protection pre-loading tracking pixels. Cross-reference with unique clicks to determine whether the high open rate corresponds to genuine engagement.

Click rate between 2–5% — Generally considered a healthy range for marketing emails. This indicates that a meaningful portion of your delivered audience is interacting with your content and links.

Click rate below 1% — Suggests that email content, link placement, or calls to action are not resonating with recipients. If your opened rate is healthy but unique clicks are low, the issue is likely with content relevance or email design rather than deliverability or subject lines.

Click rate above 5% — Indicates strong content engagement. Compare this metric across campaigns in the Email campaigns list using the clicks column to identify which content types or offers generate the highest interaction.

CTOR between 10–20% — Considered a typical range. A CTOR in this range means that among recipients who opened, a reasonable proportion found the content compelling enough to click. Benchmarks vary by industry and email type.

CTOR below 5% — Indicates that while recipients are opening the email, the content is not driving clicks. This points to a disconnect between what the subject line promises and what the email delivers, or to weak calls to action.

How metrics relate to each other

Open rate as a prerequisite for click rate — A recipient must open an email before they can click a link within it, so click rate is always equal to or lower than open rate. If open rate is low, click rate will be constrained regardless of content quality. Improving open rate by refining subject lines and send timing creates a larger pool of recipients who can then engage with your content.

Click rate vs CTOR for diagnosing issues — If click rate is low but CTOR is healthy, the problem lies in getting more people to open the email rather than in the email content itself. If both click rate and CTOR are low, the content or calls to action need improvement. Comparing the opened and unique clicks values in the Statistics section helps you isolate whether the bottleneck is at the open stage or the click stage.

Open rate and deliverability — Open rate is calculated against delivered emails, not sent emails. If your total emails delivered count in the Statistics section is significantly lower than total emails sent, a high bounce rate is reducing your delivered volume. A seemingly healthy open rate may mask the fact that many intended recipients never received the email at all.

Click rate and unsubscribe rate — Campaigns with consistently low unique clicks and rising unsubscribed values (both visible in the Statistics section) may indicate that your audience is disengaged and beginning to opt out. Monitoring both metrics together helps identify list fatigue before it escalates.

Opens and clicks over time — The Opens and clicks by day and Opens and clicks by hour charts on the Campaign overview page show how engagement is distributed after sending. A concentrated spike in opens followed by minimal clicks may indicate that the email captured initial attention but failed to sustain interest through the content.

Tracking limitations

Pixel-based open tracking — Sender tracks opens by embedding an invisible tracking pixel in each email. The open is registered when the recipient's email client loads this pixel. If a recipient reads the email with images disabled or in a plain-text client, the open is not recorded. This means open rate may undercount actual readership.

Apple Mail Privacy Protection — Apple Mail Privacy Protection pre-loads tracking pixels through proxy servers for Apple Mail users, regardless of whether the recipient actively views the email. This inflates opened values in the Statistics section. If a significant portion of your audience uses Apple Mail, treat open rate as directional and rely more heavily on unique clicks and CTOR for accurate engagement measurement.

Link-based click tracking — Sender tracks clicks by wrapping links in your email with tracking redirects. A click is registered when a recipient follows a tracked link. Links that are copied and pasted directly, or that are accessed through email clients that strip tracking parameters, may not be recorded. Click rate may therefore undercount actual link engagement.

Bot clicks and security scanners — Some corporate email security systems and spam filters automatically follow links in emails to check for malicious content. These automated clicks can inflate unique clicks and Total clicks values, particularly for audiences with high concentrations of corporate or enterprise email addresses.

Cached and pre-fetched opens — Beyond Apple Mail Privacy Protection, some email clients and proxy services cache or pre-fetch email content including tracking pixels. This can register opens that do not reflect genuine recipient engagement, contributing to inflated open rate figures.

Common issues

Open rate appears inflated compared to click rate → Apple Mail Privacy Protection is likely pre-loading tracking pixels for a portion of your audience. Use unique clicks and CTOR as supplementary engagement indicators, and review the Opens and clicks by day chart on the Campaign overview page to check whether the open pattern aligns with realistic human behavior.

Click rate is zero despite a healthy open rate → Your email may not contain tracked links, or all links may be unsubscribe or preference links that recipients are not engaging with. Verify that your email contains at least one call-to-action link and review the Clicks report tab on the Campaign overview page to confirm that links are being tracked.

Open rate drops suddenly across campaigns → A sudden decline in opened values in the Email campaigns list may indicate a deliverability issue, such as emails being routed to spam. Check the hard bounced and spam reports metrics in the Statistics section for the affected campaigns, and verify that your sending domain authentication is intact.

Click rate varies significantly between campaigns → Content relevance, offer strength, and call-to-action design differ across sends. Compare the clicks column in the Email campaigns list to identify patterns in which campaign types generate higher engagement, and use the Clicks report tab to see which specific links received the most interaction.

CTOR is high but click rate is low → The content is engaging for those who open, but too few recipients are opening the email. Focus on improving subject lines, preview text, and send timing to increase opened rates, which will expand the audience that can interact with your content.

FAQs

What is a good open rate?

Open rates vary by industry, list size, and audience. As a general reference, 15–25% is considered a healthy range for marketing emails. However, Apple Mail Privacy Protection and image-blocking email clients can inflate or deflate reported open rates, so treat this metric as directional rather than exact.

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

Click rate is calculated as unique clicks divided by total delivered emails — it measures engagement across your entire send. Click-to-open rate (CTOR) is calculated as unique clicks divided by unique opens — it measures how engaging your content was specifically among recipients who opened the email.

Why is my open rate higher than expected?

Apple Mail Privacy Protection pre-loads tracking pixels for Apple Mail users, which registers an open even if the recipient did not actively view the email. This can inflate open rate figures. Consider using click rate or CTOR as a supplementary engagement indicator.

Does Sender track unique opens or total opens?

Sender tracks both. Unique opens count each recipient once regardless of how many times they open the email. Total opens count every open event including repeat opens by the same recipient. The opened metric in the Statistics section of the Campaign overview page displays the unique open percentage and count by default.

Why might my click rate be higher than expected?

Corporate email security systems and spam filters sometimes automatically follow links in emails to scan for threats. These bot clicks inflate unique clicks values. If you notice unusually high click rates from specific domains or immediate clicks within seconds of delivery, automated scanning is a likely cause.

Can I compare open rate and click rate across campaigns?

Yes. The Email campaigns list displays opened and clicks columns for each sent campaign, allowing you to compare performance side by side. For automations, the Automations list shows opens and clicks percentages for each workflow.