Metrics
Updated
Click-through rate (CTR)
Definition
Email click-through rate (CTR) is the percentage of delivered emails in which at least one link was clicked. It is the most reliable engagement metric because, unlike opens, it requires an action.
How it works
CTR = unique clickers / delivered emails x 100. Links are rewritten through a tracking domain, which records the click and redirects to the destination.
Click-to-open rate (CTOR) = unique clickers / unique opens x 100. It isolates how well the content converts people who opened, while CTR reflects the whole send.
Security gateways that scan links before delivery can create clicks no human made, so bot filtering matters for clicks too.
Example
Same send, two ratios. CTR measures the whole send, CTOR the content.
Why it matters
Clicks are the closest email metric to revenue, and they are a positive engagement signal for mailbox providers.
Because Apple Mail Privacy Protection inflates opens, CTR is the better metric for segmenting engaged subscribers and for list cleaning.
Best practices
- Give each email one main call to action, placed high, as a button and a text link.
- Use a branded click-tracking domain so links match your sending domain.
- Segment by interest so content matches what people signed up for.
- Compare CTR across your own sends of the same type rather than against generic averages.
How Lumail handles click-through rate
Lumail tracks unique clicks per email and classifies clicks as human or bot (clicks recorded from September 6, 2026 onward). You can use a custom click domain on your own domain.
Clicks feed the engagement score, where a 10% click rate earns the full 50 click points.
Check a real message with the free mail tester or the spam tester.
Frequently asked questions
What is the difference between CTR and CTOR?
CTR divides unique clickers by delivered emails. CTOR divides unique clickers by unique opens. CTOR is less reliable now that Apple Mail Privacy Protection inflates opens.
Why do I see clicks seconds after sending?
Corporate security scanners often follow every link in an incoming message before delivering it. Those are automated clicks, not readers.
How do I improve email click-through rate?
Send relevant content to segmented audiences, use one clear call to action, and make the link visible early. Removing inactive subscribers also raises CTR because the denominator shrinks.
Related terms, tools and docs
- MetricsOpen rateEmail open rate is the percentage of delivered emails that were opened at least once.
- List managementList hygieneList hygiene is the routine of removing or suppressing email addresses that hurt deliverability: hard bounces, spam complainers, long-inactive subscribers, invalid addresses and likely spam traps..
- DeliverabilitySender reputationSender reputation is the trust score mailbox providers assign to your sending domain and IP addresses, based on how recipients and their systems react to your mail.
- DeliverabilityEmail deliverabilityEmail deliverability is the ability of your emails to reach recipients' inboxes rather than bouncing or landing in spam.
- Free toolFree spam testerCheck an email for the patterns that push mail to spam.
- Free toolFree mail testerSend a real email and get an SPF, DKIM, DMARC and content report.
- DocsBot vs human opensHow Lumail labels automated opens and clicks.
- DocsEngagement scoreOpen and click rates combined into a 0-100 score.
- DocsEmail domainsSend from your own domain instead of a shared one.
Browse every definition in the email marketing glossary.
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