Guide1 min readUpdated July 29, 2026

YouTube thumbnail size checklist

Short answer

Use a 16:9 thumbnail at or above YouTube's minimum width, prefer the current large Studio guidance when possible, and check the upload path because Studio desktop and the YouTube Data API have different file-size limits.

The quick checks

Check ratioUse 16:9 for standard long-form video thumbnails and player previews.
Check resolutionUse YouTube's current preferred large thumbnail size when possible, while staying above the minimum width.
Check upload targetStudio desktop and the YouTube Data API list different file-size limits.
Compress only when neededIf the file is too large for the target upload path, compress it while keeping text readable.

Try it: Thumbnail Size CheckerCheck thumbnail dimensions, ratio, and Studio/API file-size limits locally.Open tool

Try it: Social Image ExportFit or crop a source image into social platform export sizes.Open tool

References

Questions

Why does the checker ask for Studio or API?

The upload path matters. YouTube Studio desktop guidance and the YouTube Data API thumbnail upload endpoint list different file-size limits.

Should I always compress a thumbnail under 2 MB?

Only if your upload path requires it, such as the YouTube Data API or mobile video-thumbnail upload. For Studio desktop, check the current Studio limit.

Does Thumbnail Size Checker upload my image?

No. It checks entered dimensions and file size locally in your browser tab.

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