PDF Compressor

What PDF compression does

PDF compression reduces a file's size, typically by re-encoding embedded images at a lower resolution or quality, removing redundant data, and stripping unnecessary embedded fonts or metadata. The visible layout and text of the document stay the same — what shrinks is mostly the space taken up by images and behind-the-scenes data the PDF doesn't strictly need.

Nonkera's compressor is being built to run this process locally in your browser, so a file that might contain sensitive scanned documents or financial statements doesn't have to pass through a third-party server to get smaller.

Why file size matters

A large PDF can bounce off email attachment limits (commonly 25MB or less), take noticeably longer to upload to a job application portal or government form, and eat into mobile data when someone downloads it on the go. Image-heavy PDFs — scanned documents in particular, where each page is essentially a photograph — are often the worst offenders, sometimes running tens of megabytes for a document that's only a few pages of text and a handful of images.

Common use cases

People compress PDFs to get a scanned document under an email attachment size limit, to speed up uploading application materials to job portals with strict file size caps, and to make a large report or portfolio easier to send over a slow connection. Businesses compress PDFs before archiving large volumes of documents to save on storage, and anyone sharing a PDF over messaging apps benefits from a smaller file that sends and downloads faster.

Tips for compressing without losing readability

If your PDF is mostly text, compression will only shrink it modestly, since text itself takes up very little space compared to images — the real savings show up on scanned or image-heavy documents. When compressing something you'll need to zoom into later, like a scanned contract with small print, choose a moderate compression level and check the result before relying on the highest setting, since very aggressive compression can make fine text or fine print harder to read.

What actually happens during compression

Under the hood, PDF compression typically re-samples embedded images to a lower resolution (since most images are embedded at a higher resolution than a screen or printed page actually needs), re-encodes them using more efficient compression settings, and can also remove unused or duplicate embedded font data and metadata that doesn't affect what you see on the page. None of this touches the actual text layer of a PDF, which is why compressed documents keep sharp, searchable, selectable text even when the file size drops dramatically — the savings come almost entirely from the image and overhead side of the file, not from the words on the page. This is also why two visually similar PDFs can compress by very different amounts: one made mostly of scanned images has far more to trim than one made mostly of native, selectable text, so don't be surprised if the same compression level produces very different results on two different documents.