PDF Tools
Compress PDF
Make a large PDF smaller by re-rendering each page as an image at a lower resolution and quality. It works entirely in your browser, so the file never leaves your device.
Your file and options
Choose a compression level and rebuild the document at a smaller size.
This tool runs entirely inside your browser. Your file is never uploaded, never stored, and disappears when you close the page.
Result
Choose a file to see how much smaller it becomes.
About this calculator
This tool shrinks a PDF's file size by converting each page into a compressed image and rebuilding the document from those images. It works entirely in your browser, with no upload, account, or storage involved.
How to use it
- 1.Choose the PDF you want to shrink.
- 2.Pick how hard to compress: strong for the smallest file, light to keep pages sharper.
- 3.Select Compress PDF, wait while each page is processed, then the smaller file downloads.
Good to know
Compression here works by turning each page into a picture, so selectable text, links and form fields are lost. Keep your original if you still need them.
Scans and image-heavy documents shrink the most. A plain text PDF is already small and may not shrink much, or could even get bigger.
How it works in plain English
You choose a PDF along with two settings: a scale, which controls the resolution each page is rendered at, and an image quality level, which controls how much JPEG compression is applied. Lower scale and lower quality both produce a smaller file, at the cost of sharpness, while higher settings keep pages looking closer to the original but save less space.
Behind the scenes, the tool renders each page of the PDF as an image at your chosen scale, compresses that image as a JPEG at your chosen quality, and then places the resulting images into a new PDF, one per page. This whole sequence runs locally using JavaScript and WebAssembly, so the file is never sent to a server at any point.
It is important to understand what this trade-off means: because every page becomes a picture, any text that was previously selectable, searchable, or copyable is lost, and so are clickable links. This approach works well on scanned documents or PDFs full of photos, where the pages were already essentially images and JPEG compression can meaningfully reduce size. On a PDF that is mostly plain text, though, converting it to images often does not save much space, and can sometimes produce a larger file than the original.
Worked example
Suppose you have a 20-page scanned booklet, saved from a photocopier at very high resolution, weighing 45 megabytes. You run it through the tool at a moderate scale and medium JPEG quality. Each page is re-rendered as a smaller, compressed image, and the rebuilt PDF comes out around 6 megabytes, small enough to email, with the visible content still easy to read.
Now imagine instead a 20-page text report, originally 1.5 megabytes, made up of selectable text and no photos. Running the same compression converts every page into a JPEG picture of text. The result might only shrink slightly, or even grow larger than 1.5 megabytes, and you would lose the ability to select or search the text, which is a poor trade for that kind of document.
What compression preserves vs. changes
| Aspect | After compression |
|---|---|
| Overall file size | Usually much smaller for scanned or photo-heavy PDFs |
| Selectable / searchable text | Lost; pages become images |
| Clickable links | Lost; pages become flat images |
| Visual appearance | Slightly softer, depending on scale and quality chosen |
| Text-only documents | May shrink very little, or even grow in size |
How image-based PDF compression affects a document
Frequently asked questions
Why did my text-based PDF get bigger after compressing it?
Compression works by turning each page into a JPEG image, which is efficient for photos but not for crisp text and simple graphics. If your original PDF was already small because it used compact text and vector elements, rendering it as pixel images can end up taking more space than the efficient text-based format did.
Will I still be able to select or copy text after compressing?
No. Every page is rebuilt as a picture of that page, so any text, no matter how sharp it looks, is now part of an image rather than real characters. This means you lose the ability to select, copy, search, or click links within the document after compression is applied.
What kind of PDF benefits most from this tool?
Scanned paperwork, image-heavy brochures, or PDFs made up largely of photos tend to shrink the most, since they were effectively images to begin with and JPEG compression handles that content well. If your document is mostly typed text, this method usually isn't the right fit for reducing its size meaningfully.
How do the scale and quality settings affect the result?
Scale controls the resolution each page is rendered at before compression; lower scale means smaller, blurrier images. Quality controls the JPEG compression strength; lower quality means smaller files with more visible artifacts. Together they let you balance file size against how sharp the final pages look, depending on what you need it for.
Is my document uploaded anywhere during compression?
No. Rendering each page, compressing it, and rebuilding the PDF all happen locally in your browser using JavaScript and WebAssembly. Your file is never transmitted to a server, no account is required, and nothing is kept once you leave the page, so the process stays entirely on your own device.
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