100 MB EPUB sample

An EPUB file of exactly 104,857,600 bytes. It is a valid EPUB e-book file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 100 MB sample, test or dummy EPUB file.

sample-epub-100mb.epub

100 MB104,857,600 bytes

Download 100 MB EPUB

Created in your browser and, in browsers that can stream to disk, sent straight to your downloads list; this can take a minute. No sign-up.

Type: application/epub+zip
SHA-256: cbbae60e5fc50a90656a913bdfb433c0f89d0ba981cedbb699ba82ec99a9892b
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

A reflowable EPUB 3 book with 12 XHTML chapters, a stylesheet, a navigation document and one test-card PNG that is stored uncompressed and sized so that the book is exactly 104,857,600 bytes. Padding of 95,402,107 bytes in a private ancillary PNG chunk ("spAd", skipped by decoders) inside the image makes up the rest.

EPUB version	3.0
Chapters	12
Embedded image	PNG, 2,048 × 1,536 px
Navigation	EPUB 3 nav document
DRM	None
Container	ZIP (OCF)

First bytes of the file

The first 64 bytes of sample-epub-100mb.epub as a hex dump: offset, bytes, then the same bytes as text. The EPUB signature is 50 4B 03 04.

00000000  50 4b 03 04 0a 00 00 00  00 00 00 00 21 5c 6f 61 |PK..........!\oa|
00000010  ab 2c 14 00 00 00 14 00  00 00 08 00 00 00 6d 69 |.,............mi|
00000020  6d 65 74 79 70 65 61 70  70 6c 69 63 61 74 69 6f |metypeapplicatio|
00000030  6e 2f 65 70 75 62 2b 7a  69 70 50 4b 03 04 14 00 |n/epub+zipPK....|

Preview

EPUB files cannot be shown in a browser. Download the file and open it in an application that reads EPUB, such as Apple Books, Kobo and Google Play Books.

Where 100 MB matters

A 104,857,600-byte file: the request-body limit of Cloudflare's Free and Pro plans, and the size above which GitHub rejects a file outright.

All 100 MB sample files

Use this file for

Testing image resizing and memory use
Checking reading-system rendering
Testing conversion to other formats

Testing notes for EPUB

Re-zipping an EPUB with a generic tool usually compresses or reorders the mimetype entry, which makes strict readers reject the book.
EPUB content is HTML, so a reading system that renders it in a web view needs the same script protections as a browser.

EPUB format reference

Technical details

File name	sample-epub-100mb.epub
Format	EPUB (EPUB e-book)
Extension	.epub
MIME type	application/epub+zip
Size	104,857,600 bytes (100 MB)
Kind	Binary
Signature	50 4B 03 04
SHA-256	cbbae60e5fc50a90656a913bdfb433c0f89d0ba981cedbb699ba82ec99a9892b
Created	2026-10-23
Validation	See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility.
Preview	Not available for this file; details only
Source	Generated in your browser by this site's generator; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	Ebooks

Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Verify your copy

This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.

sha256sum sample-epub-100mb.epub     # Linux
shasum -a 256 sample-epub-100mb.epub # macOS

On Windows, run Get-FileHash sample-epub-100mb.epub -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.

Related files

Questions about this file

Is this file exactly 100 MB?: Yes. It is 104,857,600 bytes, which is 100 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 100 MB EPUB file?: A reflowable EPUB 3 book with 12 XHTML chapters, a stylesheet, a navigation document and one test-card PNG that is stored uncompressed and sized so that the book is exactly 104,857,600 bytes. Padding of 95,402,107 bytes in a private ancillary PNG chunk ("spAd", skipped by decoders) inside the image makes up the rest.
Do the sample e-books have DRM?: No. They are unencrypted EPUB 3 files with a navigation document, a stylesheet and one image.

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