PDF Compressor (Reduce Size, Shrink, Optimize)

How this page is maintained

• Steps and copy are checked against the current tool behavior.
• Browser limits, file-size constraints, or compatibility gaps are documented when relevant.
• Unless a page explicitly says otherwise, files and text stay in the browser during processing.

Compress a PDF for an Upload Form

Use this tool when the place you are uploading to accepts a flattened, image-based PDF and your original is over its size limit. The input limit is about 30 MiB. That is a different number from 30 MB: 30 MiB is 31,457,280 bytes, so a file at 30.5 MB still fits while a file at 31 MB does not. See compress a PDF under 2 MB for the byte math and a worked four-page example.

A Worked Example: 8.4 MB to 1.6 MB

Take a four-page scanned lease, 8.4 MB, and a portal that caps uploads at 2 MB.

1. Open the PDF Compressor and add the file.
2. Pick Balanced and run it. The download comes back at about 3.1 MB. Still too large.
3. Run the original again at Smaller. The new download is about 1.6 MB and fits.
4. Open the result, zoom to 100 percent, and read the smallest text on every page before uploading.

Compression can also make a file larger, so keep the original in case a preset goes the wrong way.

What Changes in the Output

Each page is rendered to an image and rebuilt into a new PDF. Text is no longer selectable, and interactive forms, links, signatures, and other document features are not preserved. Output page dimensions can shift slightly with the preset. Confirm the recipient accepts an image-based PDF before you send one.

Choose a Preset

• Balanced: start here; the least aggressive of the three.
• Smaller: lower render scale and JPEG quality for more reduction.
• Smallest: the lowest scale and quality; check small print closely.

No preset guarantees a particular file size or readability for every document. If you only need one or two pages, trim with the PDF Page Organizer first so the file starts smaller.

Processing Happens Locally

Pages render in your browser with pdf.js and are rebuilt with pdf-lib. Document contents are not uploaded to JW Tool Box. Site usage information is collected separately as described in the Privacy Policy.

How Much Smaller a PDF Gets at Each Preset

This tool does one thing: it renders every page of your PDF to a canvas, encodes each canvas as a JPEG, and rebuilds a new PDF from those JPEGs. That single fact explains everything about when it helps and when it does not. The three presets are combinations of a scale factor and a JPEG quality: Balanced renders at 95 percent of the original page size at quality 90, Smaller uses 80 percent at quality 80, and Smallest uses 65 percent at quality 65. The cards show those numbers as Scale 95% / Quality 90, and so on.

The scale is the part people underestimate, because it changes the pixel grid, not just the compression. A US Letter page is 612 by 792 points. At Balanced it is rasterized to 581 by 752 pixels, roughly 68 dots per inch. At Smaller it becomes 489 by 633, about 58 dots per inch. At Smallest it drops to 397 by 514, about 47 dots per inch, the range where body text starts to look soft at normal reading zoom. An A4 page follows the same pattern: 565 by 799 pixels at Balanced, 476 by 673 at Smaller, 386 by 547 at Smallest.

The Exact Clicks

Click the drop zone and choose a PDF, or drag one in. Wait for the file card to show the original size, then click one of the three preset cards. Click Compress PDF. A progress bar counts pages as they render, and when it finishes the file card shows the compressed size next to the ratio as a percentage, then the download starts automatically as jwtoolbox-compressed followed by a timestamp. Keep the tab open until the download begins.

The Decisions That Change the Output

Reach for Balanced when the PDF has to stay legible on screen and still carry a real size reduction: reports, invoices, slide exports. Choose Smaller for email attachments and upload portals where the receiving system has a hard ceiling. Choose Smallest for scanned documents where the content is already coarse, and avoid it for anything with fine print, footnotes, tables, or thin-stroke diagrams, because 47 effective dots per inch will smear them. One decision is made for you: the tool accepts only application/pdf files up to 30 MB.

Common Mistakes

Compressing a PDF that is mostly text and expecting a large drop. Vector text and fonts are already compact, while raster pages are not, so the reduction is modest. A more confusing outcome is a file that gets bigger, and the tool handles that case deliberately: if the rebuilt PDF is not smaller than the original, it does not download anything and tells you there were no savings rather than handing you a larger file. The mistake is assuming the run failed. It did not, it declined. The other trap is forgetting what rasterizing costs. After compression every page is an image, so text is no longer selectable, no longer searchable, and no longer accessible to a screen reader, and zooming far in shows JPEG speckle around sharp edges. Keep the original whenever anyone may need to copy text out of the document.

Where to Go Next

If the goal is a specific size limit rather than the smallest possible file, how to compress a PDF under 2 MB works through the choices in order. For anything that must keep selectable text, skip this step entirely and start from how to compress PDFs locally without losing clarity.

Key features

• Local-only rendering: PDF pages are rendered to canvas and recompressed in your browser. PDF contents are not uploaded to JW Tool Box; site usage information is collected separately as described in the Privacy Policy.
• Quality controls: Pick from three presets that trade clarity for weight. Lower settings are tuned for portals with strict upload limits.
• Predictable exports: Pages are flattened to images for consistent sizing, reducing surprises from embedded fonts or vectors.

Frequently asked questions

Related guides

• How to Compress a PDF Under 2 MB: Tested Settings and Limits

  To try to compress a PDF under 2 MB, open the PDF Compressor, choose Balanced, download the result and check its actual file size. If it remains too large, retry a stronger preset from the original file. The tool does not offer an exact “2 MB” target or guarantee that every PDF will fit. Keep the original. This compressor renders each page to a JPEG and rebuilds a PDF. Selectable text, interac…

• How to Compress PDFs Locally: Presets, Readability and Tradeoffs

  The PDF Compressor renders your PDF pages in the browser and rebuilds them using JPEG images. This can reduce image-heavy documents, but it is a lossy process. Keep your original and compare the exported file before sharing it. For a specific upload limit, use the tested PDF-under-2-MB workflow. This guide explains when compression is appropriate and which tradeoffs to check. What the compress…