Slim down a bulky EPUB — Most EPUB weight comes from embedded images. Drop in a .epub and this page re-encodes PNG/JPEG images as JPEG or WebP at your chosen quality, optionally downscales oversized artwork, then repacks the archive at maximum ZIP compression — always keeping the mimetype entry first and stored so the result stays standards-compliant. All processing happens locally.
File:
Drop an EPUB file here, or click to choose .epub — up to 200 MB
Compression Options
Choose an .epub file to begin.
Compression Report
Original: 0 KB → New: 0 KB · Saved: 0%
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What gets smaller — and what it costs
Nearly all of an EPUB's weight is images; the text itself is a few kilobytes. Re-encoding images to JPEG or WebP at a chosen quality is lossy — fine detail is gone for good, and re-compressing an already compressed book degrades it further. The ZIP repacking step, by contrast, is lossless: files that are not re-encoded come out byte-identical.
The mimetype entry must stay the first, uncompressed file in the archive (an EPUB spec rule) — that is why repacking keeps it "first and stored". Keep your original EPUB for future re-exports. To read the slimmed-down book use the E-Book Reader; to edit it see the EPUB Viewer / Editor.
