PDFToolkit

Optimize PDF

Live tool

Compress PDF Online

Upload a PDF and choose a compression level. Lower sizes can make files easier to email or submit, but very high compression can reduce image clarity.

InputPDFOutputPDFLimit25 MB per filePagesUp to 100ProcessingServer processing

Core tools can be used without creating an account.

Supported formats and limits are shown before processing.

This tool uploads your file to our server for processing. Temporary server files are removed when the processing request finishes. Cleanup is also attempted when processing fails. Browser download blobs remain only in the current browser session.

Updated 2026-07-08. This workflow has passed the core upload, processing, and download check.

Upload files

PDF - up to 25 MB

PDF

Before upload

This tool uploads your file to our server for processing. Temporary server files are removed when the processing request finishes. Cleanup is also attempted when processing fails. Browser download blobs remain only in the current browser session.

  • Already optimized PDFs may not shrink much.
  • High compression can reduce image clarity.

Drop files here

or click to choose from your device

No files selected yet.

Status: Waiting for files

  1. Reading file
  2. Uploading securely
  3. Processing
  4. Creating result
  5. Ready

Server processing returns the result directly to this browser session.

Use cases

Email attachments

Government or school upload forms

Client review copies

Archiving image-heavy PDFs

Limits

Compression works best on PDFs with removable overhead or optimizable image content. Some already-optimized files may not shrink much.

  • Already optimized PDFs may not shrink much.
  • High compression can reduce image clarity.

Steps

  1. Upload your PDF.
  2. Choose low, recommended, or high compression.
  3. Download the compressed PDF and compare readability.

File handling

The API validates PDF signatures, limits size, and returns a temporary downloadable result without creating indexable result pages.

  • Compression levels are explained before processing.
  • The tool avoids claims about guaranteed size reduction.
  • You can compare the output before sending it on.

Related tools

Merge PDFCombine multiple PDF files into one document, with file ordering before processing.Split PDFExtract selected pages or plan page ranges from a PDF.PDF to JPGExport PDF pages as JPG images for previews, thumbnails, and image-only upload forms.

Helpful guides

How to compress a PDF for emailPractical steps for reducing a PDF attachment without making it hard to read.How to reduce PDF file size without losing readabilityCompression choices that balance smaller files with readable text and images.

Compress PDF FAQ

Which compression level should I use?

Recommended compression is the safest starting point. High compression is best when size matters more than image detail.

Why did my PDF not get much smaller?

Some PDFs are already optimized or contain images that require a dedicated image recompression engine.

Can compression damage the original file?

The original upload is not modified. Always review the downloaded copy before sending it.