CTR
Click-Through Rate
Quick definition
Click-through rate (CTR) measures how often people who see a link, ad or search result click on it. It is expressed as a percentage of impressions.
Formula
CTR = (Clicks ÷ Impressions) × 100
Formula variables
- Clicks
- The number of clicks the ad, link or listing received in the period.
- Impressions
- The number of times it was shown in the same period.
Worked example
- Clicks
- 500
- Impressions
- 20,000
500 ÷ 20,000 × 100
Result: 2.5%
Out of every 100 impressions, about 2.5 resulted in a click.
How to interpret it
A higher CTR generally means the message or placement is relevant enough to attract clicks, and a lower CTR can suggest the creative, targeting or placement is not resonating.
Read it against the channel and format: search ads, display ads, email and social usually have very different typical click rates, and CTR on its own says nothing about whether those clicks lead to conversions.
When it is useful
- Comparing the pull of different ad creatives or headlines within the same campaign.
- Spotting placements or audiences that attract unusually few clicks.
- Monitoring how an email subject line or call to action performs.
Limitations
- CTR does not measure click quality: clicks can be accidental or low intent.
- Impressions are counted differently across platforms and formats, so CTR is not directly comparable between channels.
- A small number of impressions makes CTR swing widely.
- In email, CTR is often clicks divided by delivered messages, while click-to-open rate divides by opens. Check which definition a tool uses.
Common mistakes
- Optimizing for CTR alone and ignoring conversion rate or cost.
- Comparing CTR across channels or formats with different impression definitions.
- Mixing clicks from one source with impressions from another.