PDF Compressor
Files never leave your device
Drop a PDF file here
or click to browse. Pages are re-rendered as compressed images.
Compression tradeoff
  • This method rasterizes each PDF page to a JPEG image.
  • It can greatly reduce scanned or image-heavy PDFs.
  • Selectable text, links, forms, and vector sharpness are not preserved.
  • Everything runs in your browser. Your file is never uploaded.
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PDF Compressor - Reduce PDF File Size in Your Browser

Compress scanned or image-heavy PDFs by re-rendering pages at lower quality. No upload, no watermark, and clear controls for size versus readability.

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About this tool

This free PDF Compressor reduces PDF file size by re-rendering each page at a lower resolution and JPEG quality, then rebuilding the document as a new PDF. It is designed for search intents like compress PDF online, reduce PDF file size, make PDF smaller, and compress scanned PDF without upload. The tool runs fully in your browser with PDF.js and pdf-lib, so your document is processed locally instead of being sent to a server.

The important tradeoff is that this is image-based PDF compression. It can work very well for scanned PDFs, photo-heavy documents, image portfolios, screenshot PDFs, and exported slide decks. It is not ideal for PDFs where selectable text, links, form fields, bookmarks, annotations, or vector sharpness must be preserved. If your PDF needs page extraction instead of compression, use PDF Splitter; if you want to turn compressed pages into image files, use PDF to Images.

Features

  • Compress PDF files online without uploading documents to a third-party server.
  • Reduce scanned PDF file size by re-rendering each page as compressed JPEG.
  • Use Screen, Balanced, or Sharper presets for common compression needs.
  • Adjust render scale when you need smaller output or clearer text.
  • Control JPEG quality to balance readable pages against PDF file size.
  • Preview the first PDF page before starting the compression process.
  • Compare original and compressed file sizes after the PDF downloads.
  • Process image-heavy reports, receipts, portfolios, and slide decks locally.
  • Flatten text and links clearly so users understand the compression tradeoff.
  • Create compressed PDFs with no watermark, no account, and no email required.

How to Use

  1. 1
    Upload your PDFDrop a PDF into the upload area or click to browse. The browser reads the file locally and renders a first-page preview. If the PDF is confidential, this no-upload PDF compressor keeps the document on your device during the entire process.
  2. 2
    Choose a compression presetStart with Balanced for everyday PDF size reduction. Choose Screen for the smallest email-friendly PDF, or Sharper when pages contain charts, small text, or details people may zoom into. The preset controls render scale and JPEG quality together.
  3. 3
    Fine-tune scale and qualityLower render scale and JPEG quality to make the PDF smaller. Raise them if the output looks too soft or blocky. This is especially useful for scanned PDFs where the right balance depends on scan resolution, handwriting, photos, and document type.
  4. 4
    Download and compareClick Compress PDF and wait while each page is rendered, encoded, and rebuilt into a new file. The result summary shows original size, compressed size, and percentage reduction. If the file became larger, the PDF was likely already optimized; try a stronger setting or keep the original. For combining multiple PDFs afterward, use PDF Merger.

Common Use Cases

Compress scanned PDF documents
Scanned paperwork often contains one large image per page, which makes it a good fit for image-based compression. Use the Balanced or Screen preset to reduce receipts, forms, signed pages, handwritten notes, and office scans before email or upload.
Make a PDF smaller for email
Email providers and client portals often reject large attachments. Use the Screen preset when you need the smallest readable PDF for quick review. The result may not preserve selectable text, but it is often enough for visual approval or simple sharing.
Reduce image-heavy PDF reports
Reports exported from design tools, dashboards, or slide software can contain large screenshots and photos. Raster compression can reduce those PDF files when the visual layout matters more than preserving original vector objects or embedded text layers.
Compress PDF slide decks
Presentation PDFs often include full-page graphics, backgrounds, and photos. The Sharper preset keeps slides more readable, while Balanced usually creates a smaller file that is still good enough for sharing with reviewers, students, or clients.
Prepare PDFs for website uploads
CMS systems, LMS platforms, and support portals sometimes limit PDF upload size. Compressing a visual PDF locally can make the file easier to upload. For publishing page previews instead, use PDF to Images to export PNG, JPG, or WebP files.
Compress private PDFs locally
Contracts, IDs, invoices, or client scans may be inappropriate for server-based PDF compressors. This tool keeps processing in your browser. Always review the compressed output before sending it, especially when the document contains small print or important signatures.

Frequently Asked Questions

Open the PDF Compressor, drop your PDF into the upload area, choose a compression preset, and click Compress PDF. The tool uses PDF.js to render each page in your browser, encodes the rendered page as a lower-quality JPEG, then rebuilds a new PDF with pdf-lib. Your file is not uploaded to a server, so the compression happens locally on your device.

This compressor reduces file size by rasterizing each page into an image. That means selectable text, hyperlinks, form fields, annotations, and vector paths become part of the page image. This tradeoff is what makes browser-only compression possible for many scanned and image-heavy PDFs, but it is not the right method when you need to preserve searchable text or interactive PDF features.

Scanned PDFs, photo-heavy reports, exported slide decks, receipts, image portfolios, and PDFs made from screenshots usually compress best. Those documents already contain large raster images, so re-rendering pages at a lower scale and JPEG quality can reduce the final size. Text-only PDFs, vector drawings, invoices generated from HTML, and already-optimized documents may shrink only a little or may even become larger.

Use Screen when you need the smallest file for quick sharing, email attachments, or previews. Use Balanced for a practical mix of readability and file reduction. Use Sharper when the PDF contains small text, charts, diagrams, or pages that people will zoom into. You can also adjust render scale and JPEG quality manually if you want finer control.

Render scale controls how many pixels are generated for each PDF page before it is saved back into the compressed PDF. A lower scale creates fewer pixels and usually a smaller file, but text and fine details become softer. A higher scale keeps pages sharper but increases output size. For most scanned documents, the Balanced preset is a reasonable starting point.

JPEG quality controls how aggressively each rendered page image is compressed. Lower quality can make the PDF much smaller, but it may introduce blur, block artifacts, or rough edges around text. Higher quality keeps photos and text cleaner but produces a larger file. If you see visible artifacts, raise the quality or choose the Sharper preset and compress again.

Some PDFs are already highly optimized, especially text-based PDFs with embedded fonts and vector graphics. Rasterizing those pages can replace efficient text/vector instructions with full-page images, which may increase file size. If the result is larger, the source PDF is probably not a good match for image-based compression. Try a lower render scale, lower JPEG quality, or keep the original file.

PDFs that require a password to open generally cannot be processed because the browser cannot render the pages without the password. Owner-restricted PDFs may work if the browser can display them. If the file fails to load, remove the open password with a dedicated unlock workflow first, then return to the compressor with the unlocked PDF.