Inspect
EPUB File Size Analyzer
Upload an EPUB to get a detailed breakdown of file sizes inside the archive. See which images, fonts, HTML chapters, CSS files, and other assets contribute most to the total size. Use the report to decide what to compress or remove before submitting to Kindle, Apple Books, or Kobo.
Input formats
Output formats
Common uses
- Find which images are making an EPUB too large for Kindle upload
- Identify unused fonts that can be removed
- Understand the weight distribution before compression
Limitations
- Analysis is read-only — the tool does not modify your EPUB.
- DRM-protected EPUBs will show files but their content is encrypted.
Your e-book files, handled privately
This tool runs entirely in your browser. Your files are never uploaded to a server. This tool does not remove DRM or bypass copyright protection. Only upload files you own or have permission to process.
Frequently asked questions
Amazon KDP recommends keeping EPUBs under 50 MB before conversion. Files up to 650 MB are accepted but larger files may affect delivery fees.
Not from this page — use the Compress EPUB tool to reduce file size after reviewing this report.