Glossary
What is A/B testing (thumbnails)?
Thumbnail A/B testing compares two or more thumbnails to see which performs better.
A/B testing (thumbnails) explained
An A/B test shows different thumbnails for the same video to different viewers and measures which one performs better. YouTube Studio’s Test & compare feature lets eligible channels test up to three thumbnails on a video and reports a winner.
Change one big thing per variant — the face, the text or the background — so the result tells you something you can reuse.
Why it matters for thumbnails
Thumbnails are the first thing viewers see, so they influence how a/b testing (thumbnails) plays out on your channel. Read our thumbnail best practices to put this into practice, or browse the rest of the glossary.
Make your next thumbnail in minutes
Tell the AI agent what your video is about — it proposes a thumbnail, you approve it, and you can tweak it by asking.
Keep exploring
A/B test thumbnails
How to run thumbnail tests that teach you something — with YouTube’s Test & compare.
Learn more →Edit by asking
Change any thumbnail with a sentence — bigger text, new background, different expression.
Learn more →Click-through rate (CTR)
Impressions click-through rate is the share of thumbnail impressions that turned into views.
Learn more →