Click-Through Rate (CTR) is the percentage of people who click on a link, ad or search listing out of everyone who saw it, calculated by dividing clicks by impressions.
Also written as CTR.
CTR tells you whether your message is landing. A low CTR on an ad or a search result usually means the headline, offer or audience is wrong, not that the channel is broken.
For a small business on a tight budget, CTR is an early warning signal. You can read it within hours of a campaign starting, long before you have enough sales data to judge anything else.
On Google Ads, a strong CTR also lowers your cost per click, because the platform rewards ads people want to click. CTR is not just a vanity metric, it directly affects what you pay.
A cafe runs a Google Ad that is shown 2,000 times in a week and gets 60 clicks. CTR is 60 divided by 2,000, which is 3 percent.
If a second version of the ad, with a sharper headline about weekend bookings, is shown 2,000 times and gets 120 clicks, that is a 6 percent CTR.
The second ad is pulling twice the interest from the same exposure. On Google Ads it would also tend to cost less per click, so the better message wins twice over.
In-House writes and tests ad creative through the advertising agent, watching CTR to find the messages that earn the click before spend builds up behind a weak one.