CTR · click-through rate
CTR (click-through rate) is the proportion of people who click on an ad among those who saw it. It measures how compelling your message is.
The formula
CTR = (Clicks ÷ Impressions) × 100
A concrete example
Example
200 clicks for 10,000 impressions: CTR = (200 ÷ 10,000) × 100 = 2%.
Why it matters
A good CTR lowers your costs: platforms reward relevant ads with better placement and a lower CPC. It is a direct lever on profitability.