Compress PDF Files Online
Keep text selectable, or shrink it as an image
Smart mode repackages the PDF while keeping its text layer intact. Image mode renders pages to JPEGs at the DPI and quality you choose, giving you more control over the size-versus-quality trade-off.
Compress your PDF
Upload a PDF, choose a mode and settings, and process it directly in your browser.
Drop your PDF here
or browse files
Higher DPI means sharper text but a larger file.
3. Advanced options
Removes common document properties like title, author, and creator fields.
4. Pages to include
Only the pages you enter will be included in the output PDF.
Your file is ready
Saved 45%
of file size
Original size:
Compressed size:
Page 1 preview at selected settings
Every smaller PDF involves a trade-off
Smart mode repackages PDFs while keeping text selectable. Image mode renders pages as compressed JPEGs to maximize size reduction.
Two different mechanisms
Contracts and text-heavy reports need to stay searchable and copyable, so shrinking them shouldn't disrupt the text layer. Scanned files are already pixel-based, so converting them to compressed JPEGs reduces file size significantly.
Smart mode repackages the PDF structure so existing text remains selectable and searchable. Image mode renders each page to a JPEG image at the quality and resolution you choose, offering higher size reductions.
Every control and what it changes
Smart (text kept)
Repackages pages without rasterizing them, keeping text selectable and searchable.
Image mode
Renders pages as JPEG images for higher file-size reduction, with text no longer selectable.
DPI and quality level
DPI controls pixel density; quality sets JPEG compression. Together they define image sharpness.
Pages to include
Include only specific page ranges in the output to keep file size smaller.
Metadata removal
Strips common document properties and metadata fields.
Four steps, choose the right balance
Choose the mode first, then adjust quality, DPI, metadata, and page selection for the output you need.
Upload your PDF
Drag it onto the upload area or click Select PDF. The document renders immediately in your browser.
Choose mode and settings
Decide what you need:
Compress
Click Compress PDF. A progress bar tracks page rendering in Image mode.
Check and download
Compare original and compressed sizes, review the page preview, and save your file.
What image compression can achieve
Example of image compression applied to a scanned report.
Large files can run into attachment, upload, or sharing limits.
Smaller output with page quality determined by the selected DPI and JPEG quality.
When PDF compression is useful
Situations where file size limits make compression necessary.
| Situation | Recommended approach |
|---|---|
| Email attachments | When an email service has a strict size limit, Image mode can help reduce large scanned PDFs before attaching them. |
| Contracts & legal filings | Text needs to remain selectable for search and citation — Smart mode preserves the text layer without rasterizing. |
| Portfolios & resumes | When a job application portal has a strict file upload cap, Image mode helps keep resumes or portfolios within limits. |
| Scanned archives | Scanned pages respond well to image compression, with final quality governed by your chosen DPI and JPEG quality settings. |
| Website downloads | Smaller PDFs require less data to download, reducing transfer time and bandwidth usage for site visitors. |
| Cloud storage limits | Reducing unnecessarily large PDFs helps manage shared or personal storage quotas more efficiently. |
How each compression mode and level changes your PDF
Smart keeps text selectable, while Image mode uses JPEG compression at four quality levels.
Basic
The highest-quality preset, using JPEG quality 0.90. It usually preserves more image detail while producing less aggressive size reduction.
Recommended
Uses JPEG quality 0.75 as the default balance between visual detail and file size.
High
Uses JPEG quality 0.50 to produce a smaller file with more noticeable quality loss — well suited to screen viewing or internal drafts.
Extreme
Uses JPEG quality 0.30 as the most aggressive preset, prioritizing file-size reduction over image quality.
When the output isn't what you expected
Common issues and how to resolve them quickly.
Output looks blurry
DPI is set too low or the compression level is too aggressive.
Raise DPI to 150 or 300, or switch to Basic or Recommended level.
File got larger, not smaller
The source PDF was already heavily optimized or very small.
Try Smart mode, a stronger compression level, or include fewer pages in the output.
Text isn't selectable anymore
Image mode was used, converting pages to JPEGs without a text layer.
Re-run using Smart mode if selectable text is required.
Compression takes a while
Large multi-page PDFs at high DPI take longer to render.
Lower DPI, or include fewer pages in the output.
Won't compress
The PDF may be encrypted, password-protected, corrupted, or unsupported by browser libraries.
Try an unencrypted copy or open and re-save the PDF before compressing.
Output looks blurry
Why: DPI too low or level too aggressive.
Fix: Raise DPI or use Basic/Recommended.
File got larger
Why: Source was already optimized.
Fix: Try Smart mode or include fewer pages in the output.
Text not selectable
Why: Image mode was used.
Fix: Switch to Smart mode.
Compression is slow
Why: Many pages at high DPI.
Fix: Lower DPI or include fewer pages in the output.
Won't compress
Why: Encrypted or unsupported PDF.
Fix: Try an unencrypted copy.
Practical compression tips
A practical order of steps to get the result you need on the first try.
Start with Recommended
It provides a balanced default for most files — only move to High or Extreme if the file is still too large.
Use Smart mode for text documents
Contracts, reports, and ebooks keep selectable text while the PDF is repackaged without rasterizing page content.
Include only the pages you need
Narrowing down page ranges shrinks large documents dramatically when you only need specific sections.
Review the page 1 preview
Check the preview at your chosen settings before downloading to ensure quality meets your needs.
Remove metadata when sharing
Stripping author and property fields helps protect privacy and trims extra data.
Keep your original file
Image compression discards image detail that cannot be recovered once saved.
Common questions about PDF compression
Clear answers about browser-based processing, compression settings, and output quality.
Is my PDF uploaded?
The compression code processes the PDF in your browser. This page does not upload the PDF to AllInOneTools servers for compression.
Why can't I select text in the compressed PDF?
That happens in Image mode: each page is rendered to a JPEG image, which can produce a much smaller file but removes the original text layer. Use Smart mode if you need text to remain selectable and searchable.
Will compressing reduce the quality of my PDF?
In Image mode, yes — the Compression Level and DPI control that trade-off. Basic keeps more image detail; Extreme uses the lowest JPEG quality setting for stronger size reduction at the cost of sharpness. Smart mode does not rasterize page content.
How much will my file size be reduced?
It depends on the mode and settings you pick. Image mode can achieve significant reductions on scan-heavy documents, but results vary based on the source file.
What do the compression levels do?
They set the JPEG quality used in Image mode. Basic keeps the most detail with a larger file, Recommended balances quality and size, High noticeably reduces quality for a smaller file, and Extreme uses the lowest JPEG quality setting to prioritize reduction.
What happens to my file after I'm done?
The compression process runs in your browser, and this tool does not send the PDF to AllInOneTools servers for processing. Your original file is not modified; the compressed PDF is created as a separate download.
How the browser-based compression works
Because processing runs locally in your browser, I documented the client-side implementation covering pdf-lib structure repackaging and the canvas-to-JPEG pipeline.
How to Compress PDF Files in the Browser Using JavaScript
Covers the browser-side implementation behind this approach, including PDF handling, canvas rendering, JPEG conversion, and local file processing.