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Reference library · Digital attribution
Click-Through Rate (CTR)
Click-through rate is the percentage of ad impressions that result in a click, calculated by dividing clicks by impressions. It measures how well a creative and its placement prompt the audience to act, separate from what happens after the click.
Formula
Worked example
A display campaign running in Poland serves 850,000 impressions and logs 2,975 clicks. CTR = 2,975 / 850,000 x 100 = 0.35%, which sits inside the normal 0.3-0.5% band for standard display banners, so the buyer reads this as a healthy creative/placement pairing rather than a flag to pause.
How it is used
Planners use CTR to compare creative variants or placements within the same channel and format, so they can rotate out weak banners or shift budget toward stronger-performing ad units. It also feeds early in-flight optimization before conversion data has accumulated enough volume to trust. The common mistake is putting CTR from different formats or channels on one scale, since search, display, and social carry structurally different baseline CTRs.
The common mistake
Don't compare CTR across different ad formats or channels; only compare it within the same format and placement type.