YouTube shows only the first 100 to 120 characters of a description on desktop and even fewer on mobile, so the opening line should state the video’s topic, key keywords, and any needed call to action. The full description can reach 5,000 characters, giving creators room for links, timestamps, credits, and other details.
Essential Concepts
Front-load key info
100 to 120 characters visible
5,000-character limit
Use full description for links and timestamps