Compress PDF online — free, fast and private

Reduce PDF file size while keeping the best possible quality. With Pixpoo you can compress PDF online for free, right in your browser — no sign-up, no watermark, and your files are processed locally rather than sent to Pixpoo’s servers.

About Compress PDF

Compressing a PDF means rebuilding it so that it takes up less space. Pixpoo does this by rendering each page at a chosen resolution and storing it as a JPEG image inside a new PDF. Everything that was not visible on the page — unused objects, embedded font programs, leftover editing history — is simply not carried over, which is often where a surprising amount of the size was hiding.

This is a genuinely lossy process, and it is worth being clear about the trade-off before you use it. Because pages are rebuilt as images, the finished PDF has no text layer: you cannot select, copy or search the text, and a screen reader cannot read it. What you get in return is a file that is frequently a fraction of its original size and looks essentially the same on screen. For a scanned document that was already a stack of images, you lose nothing you had. For a text-based PDF exported from Word, you are trading something real away.

How much smaller the file gets depends almost entirely on what is inside it. Scans and image-heavy documents compress dramatically, because photographs are exactly what JPEG is good at. Documents that are mostly text and vector diagrams compress far less, and were often small already. If the rebuilt file would end up larger than the original — which can happen with an already-optimised PDF — Pixpoo detects that and gives you back the smaller of the two, so you are never handed a bigger file than you started with.

When should you compress a PDF?

Compression is the right tool when size is the problem and a text layer is not needed. Common cases:

• Getting a scanned document under an email or upload size limit
• Reducing a photo-heavy portfolio, brochure or catalogue before sharing it
• Shrinking a batch of scanned receipts or invoices before archiving them
• Making a large document practical to send over a slow or metered connection
• Cutting storage for documents you need to keep but rarely open
• Preparing a file for a portal that rejects anything above a fixed size

Compress PDF options explained

Compression is a trade between file size and image detail, and every control below moves that trade in one direction or the other. Here is what each one does and when to change it.

Extreme Compression

Renders pages at 72 DPI with JPEG quality set to 50%. This is the smallest output the tool produces.

Choose it when size is the only thing that matters and the document only needs to be readable on a screen — a scan you are archiving, or a file that has to squeeze under a stubborn upload cap. At 72 DPI the result is screen resolution, so it will look soft if anyone prints it, and small type may lose definition. Check the result before sending it on.

Recommended Compression

Renders pages at 110 DPI with JPEG quality at 72%. This is the default and the setting most documents should use.

It is the balance point: a substantial size reduction on image-heavy files while keeping pages sharp enough to read comfortably on any screen and acceptable on paper. Start here, look at the result, and only move to another level if the size or the sharpness is not what you needed.

Low Compression

Renders pages at 150 DPI with JPEG quality at 88% — the highest-fidelity preset, and the largest output of the three.

Use it when the document will be printed, or when it contains fine detail that matters: small print, engineering drawings, tables of figures, photographs someone will look at closely. 150 DPI is a reasonable print resolution, so pages hold up on paper rather than only on screen. Expect a more modest size reduction in exchange.

Custom Compression

Unlocks the Image Quality and Resolution sliders so you can set the two values yourself rather than taking a preset.

Worth using when you have a specific target to hit — a hard size limit, or a print requirement the presets bracket but do not match. Adjusting either slider switches the level to Custom automatically, so you can start from a preset and tune from there rather than beginning from scratch.

Image Quality

Sets the JPEG quality used for each rebuilt page, from 30% to 100%. Lower values discard more detail and produce a smaller file.

This is the control to reach for when the file is close to the size you need. Quality behaves non-linearly: dropping from 90% to 70% usually saves a lot and costs little visibly, while going below about 50% starts to show as blocky patches around text edges and in flat areas of colour. Photographs tolerate low quality better than pages of small type do.

Resolution (DPI)

Sets how many pixels per inch each page is rendered at, from 48 to 200. It has a larger effect on file size than quality does, because halving the DPI quarters the pixel count.

Match it to where the document is going. Around 72 DPI is screen-only. 100 to 120 reads well on screen and is passable on paper. 150 and above is genuinely printable. Going beyond roughly 200 rarely helps, since you are then storing more pixels than the original page contained. If one control is going to fix an oversized file, it is usually this one.

Grayscale conversion and Remove metadata

Grayscale conversion converts each page to shades of grey before it is compressed. Remove metadata clears the document title, author, subject and keywords from the output.

Grayscale is worth ticking for colour scans that only need to be legible — discarding the colour channels reduces size further on top of whatever the quality and DPI settings already save. Remove metadata is on by default and is about tidiness rather than protection: because the compressed file is built as a new document, the original’s author, title and software details are already left behind whether the box is ticked or not. What the option adds is blanking those fields in the new file and naming Pixpoo as the producer. Note that a creation timestamp is still written into the output.

How compression rebuilds the file

The panel in the tool states the mechanism plainly: pages are rebuilt as optimised images, and unused objects and embedded fonts are dropped.

It is worth reading before you compress something irreplaceable. Because the page is rebuilt rather than edited, the text layer, bookmarks, form fields, annotations and links do not survive into the new file. Always compress a copy and keep the original — compression cannot be undone, and there is no way to recover the text layer from the compressed result.

Why use Pixpoo for Compress PDF?

• Four levels from screen-only to print-ready, with sliders when the presets do not fit
• Separate control over image quality and resolution, rather than one vague slider
• Never returns a file larger than the one you started with
• The whole rebuild is local; nothing about your file reaches Pixpoo’s servers
• Free with no account or email required, and no branding added to the smaller file
• Optional metadata removal, so document properties are not passed on with the file

Compress PDF features

Compress PDF limitations

Compression in Pixpoo is lossy by design: every page is re-rendered as a JPEG image, so the output has no selectable, searchable or screen-reader-accessible text, and any bookmarks, form fields, annotations and hyperlinks are not carried into the new file. Pages are flattened onto a white background, so transparency is lost. Text-based PDFs generally compress far less than scans and may not be worth compressing at all. If the rebuilt file would be larger than the original, Pixpoo returns the smaller file instead. Password-protected PDFs must be unlocked first. Metadata is not fully stripped: the output carries a creation timestamp even with Remove metadata ticked.

Common Compress PDF questions

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