The Programmatic Glossary
A practical glossary designed to help marketers, advertisers and ad-tech professionals understand the terminology that powers programmatic advertising
Measurement & Analytics
Click-through rate (CTR)
The percentage of people who see an ad and then click on it. A CTR of 0.5% means that for every 1,000 people who saw the ad, 5 clicked on it. Higher CTR generally means the ad is more engaging or relevant to its audience.
HOW IT WORKS
CTR is calculated by dividing the number of clicks by the number of impressions, then multiplying by 100. Formula: CTR = (Clicks ÷ Impressions) × 100. It's tracked automatically by ad servers and DSPs via click-tracking pixels and redirect URLs embedded in the ad.
EXAMPLE
A retailer runs a banner ad that generates 50,000 impressions and 200 clicks. CTR = (200 ÷ 50,000) × 100 = 0.4%. The industry average for display is 0.05–0.1%, so 0.4% is strong performance.
RELATED TERMS
Impression | CPM | Video completion rate (VCR) | Attribution | Viewability
