Why ePub files are much smaller than mobi or PDF files for the same book

Question

When I buy e-books, I download all available formats. I noticed that file sizes for different formats can be noticeably different, and epub is usually much smaller.

For instance:

• PDF - 5.7mb;
• ePub - 2.7mb;
• Mobi - 8.1mb.

Or:

• PDF - 4.5mb;
• ePub - 1.8mb;
• Mobi - 5.3mb.

I looked through them and tried to confirm that the content is the same and they seem (i.e. there are no large images). Can anyone explain why the epub is so smaller than the other two?

Answer 1

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Answer 2

epubs -. epub XHTML CSS2 , CSS3, , epub, .

Answer 3

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Answer 4

.pub ( zip ).

.mobi do not shrink. If you archive the mobi file, you may get a smaller file than epub.

By the way, this makes text search much faster on mobi files than on epub.