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FilesKit

Compress PDF files

Make PDFs smaller by optimizing the images inside them. Text, fonts and vector graphics stay untouched. Compression runs in your browser, so your documents are not uploaded.

PDFProcessed in your browser
The tool loads in your browser…

Features

  • Three levels

    Less compression (JPEG quality 85, 200 dpi), Recommended (70, 150 dpi) and Extreme (50, 100 dpi).

  • Sized to the page

    Each image is scaled down to the chosen resolution measured against the largest page it appears on, so it is never sharper than needed.

  • Only when it helps

    An image is replaced only if the new version is smaller, and if the whole file would not shrink you get the original back.

  • Structure is preserved

    The PDF is edited in place, not rebuilt, so document metadata, links and text remain.

How to use Compress PDF

  1. Choose one or more PDFs or drop them onto the page.
  2. Pick a compression level.
  3. Select Compress and wait for each file to finish.
  4. Check the savings and download the compressed PDFs or the ZIP.

Supported formats

AcceptsPDF
ProducesPDF

JPEG images and 8-bit RGB or grayscale images are re-encoded. Other image types are left as they are.

Limits and things to know

  • Up to 20 files, 100 MB each and 300 MB in total. Password-protected or damaged files are reported by name.
  • PDFs that are mostly text or vector graphics barely shrink, because only images are optimized. Fonts are not subsetted.
  • Images with transparency, image masks, CMYK or indexed colours, 16-bit images, JPEG 2000, JBIG2 and CCITT images are left untouched.
  • Re-encoding images is lossy. Colour profiles of re-encoded images are replaced by standard RGB.
  • There is no mode that turns pages into pictures; that would give smaller files but would remove selectable text.

Privacy and processing

Images are extracted, re-encoded and written back by code running in a Web Worker in your browser, using pdf-lib and your browser’s image engine. FilesKit has no server that receives your PDFs.

Common uses

  • Email size limits

    Shrink a scanned document or photo report that is too big to attach.

  • Upload portals

    Get a PDF below the maximum file size of an application or tax form.

  • Archiving scans

    Reduce the size of image-heavy documents before storing them.

  • After Images to PDF

    Compress the PDF you just made from large photos.

How this differs from other approaches

Online PDF compressors upload your file to a server where a more powerful engine may squeeze harder. FilesKit compresses on your device, so nothing is uploaded, but its savings are limited to image optimization. Desktop tools can also optimize fonts and structure.

Frequently asked questions

Why did my PDF not get smaller?

It probably contains little or no image data, or only image types that are left untouched. The result screen tells you when the original was kept.

Will text still be selectable?

Yes. Only embedded images are changed. Text, fonts and vector graphics are not touched.

Which level is best?

Recommended is a good balance. Use Extreme when size matters most, and Less compression for documents with detailed photos.

Are my documents uploaded?

No. Compression runs in your browser and FilesKit has no server that receives files.

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