Compress PDF

Almost every "compress PDF" service on the internet quietly does the rasterise trick and does not tell you, which is why people are so often surprised when the text in their compressed file can no longer be selected or searched. The distinction matters enormously depending on what the document is. A scanned contract is already nothing but images, so rasterising costs you nothing you had and can cut the file by 90% or more. A text-based report is the opposite case: rasterising it destroys the text layer, breaks accessibility for screen-reader users, makes the document unsearchable, and frequently produces a file that is actually larger than the original, because a page of crisp text stored as instructions is far more compact than the same page stored as a photograph of itself. That is why lossless is the default here and why the tool tells you plainly when it found little to save — a small saving on an already-efficient file is the correct answer, not a failure.

Lossless mode reserialises the document with cross-reference and object streams enabled and writes only objects the document graph still reaches, which is where the saving on edited files comes from. Rasterise mode renders each page at your chosen DPI, encodes it as a JPEG at your chosen quality, and places that image on a new page of the original dimensions.

Lossless mode cannot recompress the images already inside the pages, so a PDF that is large because it contains photographs will barely shrink — often by only a few per cent. Rasterise mode is a one-way conversion: text stops being selectable, searchable and readable by screen readers, and it is capped at 200 pages. Encrypted and password-protected PDFs cannot be rebuilt at all. Neither mode can beat a purpose-built desktop tool that resamples individual embedded images.

A 24 MB phone-scanned contract drops to about 1.5 MB when rasterised at 120 DPI and quality 70 — comfortably under an email limit, and still perfectly readable on screen.

1. Choose your PDF file.
2. Start with lossless mode and see what it saves.
3. If you need more and the document is a scan, switch to rasterise.
4. Check the before-and-after figures, then download.

• Rasterising a text document and losing the ability to search or select it.
• Expecting lossless mode to shrink a file that is large because of photographs.
• Overwriting the original with the compressed copy before checking the result.
• Choosing 72 DPI for a document that will later be printed.

Reduce the size of a PDF two ways, and the tool is explicit about the trade-off. Lossless mode repacks the file structure and leaves every page exactly as it was, with text still selectable. Rasterise mode redraws each page as a compressed image, which shrinks scans dramatically but turns the text into a picture.

Anyone hitting an email attachment limit or an upload cap on a portal that will not accept the file as it is.

• Two honest modes, with the cost of each stated before you choose.
• Lossless mode never degrades a page — the content is identical, only stored better.
• Reports the exact before-and-after size rather than a vague promise.
• Contracts, statements and scans never leave your device.

• Getting an attachment under a 10 MB email limit.
• Shrinking a phone-scanned document before uploading it to a portal.
• Cleaning up a PDF that has grown after repeated edit-and-save cycles.
• Removing document metadata and reducing size in one pass.