Email Open Rate measures whether your subject line worked. Email Click Rate measures whether your email content worked. Together, they reveal where in the email funnel your audience drops off — and where to focus your next improvement.
The core distinction
Email Open Rate and Click Rate capture two separate decisions your audience makes. Open Rate tracks the percentage of delivered emails that were opened, reflecting how compelling your subject line, sender name, and preview text were. Click Rate tracks the percentage of delivered emails that received at least one link click, reflecting how well your content, layout, and calls to action performed.
The distinction matters because a high Open Rate paired with a low Click Rate points to a specific problem: your subject line promises something your email doesn't deliver. Readers opened it, then left without acting. Diagnosing that gap is impossible if you treat the two metrics as interchangeable.
How they work together
Open Rate and Click Rate form a sequence. A reader must open an email before they can click anything, so Open Rate sets the ceiling for engagement. If your Open Rate is 20%, no more than 20% of recipients can ever click — Click Rate will always be lower.
Marketers often compare these metrics together to calculate Click-to-Open Rate (CTOR): the percentage of openers who also clicked. CTOR isolates content performance from subject line performance, giving you a cleaner read on whether the email body itself is resonating.
For example, if 1,000 emails are delivered, 200 are opened (20% Open Rate), and 40 clicks are recorded (4% Click Rate), the CTOR is 20% — meaning one in five openers engaged with the content. That ratio tells you more about content quality than either metric alone.
When to use each
Use Open Rate when you're evaluating subject lines, sender names, or send-time experiments. It answers the question: did we earn attention at the inbox level?
Use Click Rate when you're evaluating the email itself — the offer, the copy, the layout, or the call-to-action placement. It answers the question: did the content motivate action?
If you're running an A/B test on subject lines, Open Rate is the right success metric. If you're testing two different email layouts or offer framings, Click Rate — or CTOR — gives you a more accurate signal. Choosing the wrong metric for the wrong test leads to false conclusions about what's actually working.
