EPUB Optimizer

Optimize images, apply CJK spacing, convert Chinese text, highlight code, and format Japanese kana within EPUB files.

Input

Optimize and process EPUB files completely in your browser. Compress images, clean spacing, convert Chinese text, and add formatting.

Image Optimization

Compression Mode

Quality80%

Convert to WebPConvert PNG and JPEG images to WebP format for better compression.

Resize large imagesLimit max width while keeping aspect ratio. Desktop/Tablet/Mobile presets.

Content Compression

Enable CompressionMinimize or format HTML and CSS content.

Remove unused filesRemove unused images, CSS, fonts and HTML files not referenced in the EPUB.

Font Settings

Embed Used FontsScan EPUB for font usages and embed matching local system fonts.

Override Default FontOverride body font with a selected local system font.

Optimize FontsEnable font file size optimization.

Text Operations

CJK Spacing (Pangu)Insert spacing between CJK and half-width English characters.

Chinese Translation

Dialogue & Quote ColoringHighlight dialogues, quotes, keywords, and brackets using custom colors.

Japanese Kana RubyGenerate pronunciation ruby annotations for Japanese kana.