PDF Compressor
Reduce PDF file size while keeping quality readable.
About PDF Compressor
PDF Compressor creates a new PDF by rendering each source page as a compressed JPEG image. It can help with image-heavy documents such as scans when you need a smaller attachment or upload. Choose Smallest file, Balanced or Best quality depending on the trade-off between file size and visual detail.
This particular compression method changes the document’s structure: text in the output is no longer selectable or searchable, even if it was text in the original. It is therefore a better fit for viewing and sharing than for preserving an editable or accessible document. Keep the original, compare the reported file sizes, and inspect small text in the downloaded copy before replacing an attachment.
How to use PDF Compressor
- Select the source
Choose a PDF in the upload area.
- Choose a preset
Read the image-rendering note, then select Smallest file, Balanced or Best quality.
- Compress
Select Compress PDF. The progress indicator shows the pages being processed.
- Compare the output
Review Original size and Compressed size, download the new PDF, and inspect its readability.
Example: A scanned handout
Try Balanced on an image-heavy scan. If fine print becomes hard to read, retry with Best quality. Keep whichever result meets both your upload limit and readability needs; a size reduction is not guaranteed.
How it works
The tool uses PDF.js to draw each page onto a browser canvas. The selected preset controls the rendering scale and JPEG quality. It then embeds that JPEG in a new PDF page with matching displayed dimensions. Repeating this for every page produces an image-based document: the appearance is retained at the chosen resolution, while the original text and vector objects are replaced by pixels.
Lower JPEG quality can reduce image data but may introduce visible artifacts. A higher rendering scale gives small details more pixels and usually requires more storage. The size comparison is measured from the input file and the generated output, rather than predicted from the preset. A document that already contains efficient text or compressed images can become larger. The tool reports that possibility, so compare the actual sizes rather than assuming any preset will shrink every PDF.
When is this useful?
- Prepare image-heavy scans for an attachment limit.
- Make a viewing copy of a scanned handout.
- Compare file size against the readability of small print.
Things to know
- Selectable text, searchability and original interactive document features are not preserved.
- Compression may increase file size; a smaller result is not guaranteed.
- Large documents can take time and browser memory. Password-protected PDFs may not open without an unlocked copy.
Privacy & processing
The browser reads the selected PDF, renders its pages on a local canvas and builds the output PDF. Source document bytes are not uploaded to a ToolMyth server for compression. The PDF rendering worker is a browser worker, not a remote processing service.
Frequently asked questions
Will I still be able to select text?
No. This tool turns each page into an image. Keep the original for text selection, search and workflows that depend on text objects.
Which preset should I try first?
Balanced is a reasonable starting point. Inspect the output, then try Best quality for finer detail or Smallest file for a stronger size trade-off.
Why is the new PDF larger?
Rendering efficient text or already-compressed pages as JPEG images can add data. Compare the displayed sizes and keep the original when compression does not help.
Does the compressor change my source file?
No. It offers a separate compressed.pdf download and does not overwrite the selected file.