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Compress PDF

Free
Shrink PDF file size with adjustable quality (Light, Balanced, Strong). Server-side via Ghostscript — keeps text searchable, embeds web-optimized linearization. Falls back to your original if compression doesn't actually help.

What you'll get: a smaller PDF with the same content. Three quality levels — Light (~10–30% smaller, almost no visible change), Balanced (~30–50%, the default), Strong (~50–80% but visible image-quality drop). If your PDF is already well-optimized, we'll return the original and tell you we couldn't make it smaller. For another use, try PDF Inspector (see what's in your file before compressing).

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Stays in your browser
Free tools run fully on-device — nothing is uploaded to a server.
No watermarks
Clean output, no branding, no daily limits.
Free forever
No signup required. Seriously.

Why people compress PDFs

PDF size matters more than people admit — email attachment limits, slow page loads on shared drives, mobile data caps, courier upload portals that reject anything over 10 MB. Most PDFs carry redundant image data, oversized embedded fonts, and rasterized scans that compress dramatically with no perceptible quality loss. The right level depends on what you're using the file for: print needs Light, email needs Balanced, archiving on a phone needs Strong.

Email attachment limits
Gmail and Outlook cap at 25 MB per email; many corporate gateways stop at 10 MB. A scanned 50-page contract often lands at 35 MB and bounces silently. Balanced quality typically gets you well under the limit without anyone noticing the difference.
Court & government e-filing portals
Many e-filing systems enforce 10 MB or 5 MB caps and reject anything larger. Strong quality compresses scanned exhibits aggressively while keeping text searchable — the form layer survives, the embedded scans get downsampled.
Shared-drive performance
Google Drive and OneDrive load PDFs faster when they're linearized (a side-effect of all three quality levels here). Smaller files also use less of the recipient’s storage quota — relevant when you're sending the same proposal to 50 prospects.
Web embed & download performance
PDFs embedded on a website (specs, manuals, datasheets) render the first page faster after compression because Fast Web View linearization rearranges the byte stream so page 1 streams before pages 2-N download.
Mobile sharing & data caps
AirDrop, WhatsApp, and SMS attachments all degrade UX past a few MB. Strong quality cuts most scanned PDFs by 60-80% — visible quality drop on photographs, almost invisible on text-only documents.

How Compress PDF works

Three steps, no signup, no uploads.

  1. STEP 1
    Drop your PDF
    Up to 50 MB. Your file is uploaded to our server (this is one of the few tools that can’t run in the browser — Ghostscript needs to be invoked server-side).
  2. STEP 2
    Pick a quality level
    Light keeps the file print-ready (10–30% smaller). Balanced is the email-friendly default (30–50%). Strong is aggressive — visible image-quality drop, best for web-only PDFs (50–80%).
  3. STEP 3
    Compress & download
    Ghostscript downsamples images, subsets fonts, removes redundant objects, and linearizes the output for Fast Web View. Result is text-searchable, color-faithful at the level you chose, and downloadable as <name>-compressed.pdf.

What makes pdfcraft ai different

  • Same engine Chrome uses
    PDFium is Google's PDF engine — the one that powers Chrome's built-in PDF viewer. We compile it to WebAssembly so it runs in your browser at near-native speed.
  • 100% local processing
    Most free PDF tools upload your file to a server, process it, and stream the result back. We don't. Your file lives in your browser tab and never touches our infrastructure. Verifiable in your browser's Network panel.
  • No watermark, no signup, no daily limit
    Convert 1 PDF or 1,000. We don't gate on volume because there's nothing to gate on — the engine runs on your machine.
  • Honest about limitations
    When something the tool can't do (encrypted PDFs, cross-reference streams), we tell you clearly instead of failing silently. Same for partial results: sampled vs exact, embedded vs not.
  • Open standards, free engines
    PDFium is BSD/Apache licensed (free for any use). We don't pay vendor license fees and pass that savings on to you (and to ourselves) as a free, ad-supported tool with no upgrade-to-pro pressure.

Frequently asked questions

Will compression ruin my images?
Depends on the level you pick. Light keeps images at 300 DPI — invisible loss. Balanced drops to 150 DPI — fine for email and screen viewing, mostly invisible. Strong drops to 72 DPI — visible quality loss on photographs, OK for text-with-occasional-images. The tool tells you which level produced what reduction so you can compare.
What if my PDF is already optimized?
If we can&rsquo;t shave at least 5% off the file, we return your original PDF unchanged with a note explaining we couldn&rsquo;t make it smaller. No silent inflation — your bit-identical original comes back so metadata, signatures, and form fields stay exactly as you uploaded them.
Is text still searchable and copyable?
Yes at all three levels. Compression downsamples raster images and re-encodes streams; it doesn&rsquo;t flatten text into pixels. Ctrl-F still finds words; copy-paste still pulls real text. The exception is if your &ldquo;PDF&rdquo; was a scanned-image PDF without a text layer to begin with — compression can&rsquo;t add text that wasn&rsquo;t there. Run OCR (Searchable PDF) first if you need that.
What about my PDF&rsquo;s metadata, bookmarks, and form fields?
Metadata (author / title / subject / keywords) is preserved. Bookmarks and the document outline are preserved. Form fields are preserved as fillable fields. Annotations and comments are preserved. The compression operates on object streams and image data, not on the document structure.
Why does this tool require sign-in when most others don&rsquo;t?
Compression runs server-side via Ghostscript — it consumes real CPU + memory + disk on our servers. Sign-in lets us tie usage to an account so we can fairly distribute that capacity and prevent abuse. The browser-based tools (merge, split, rotate, etc.) can stay anonymous because they run on your computer, not ours.
Are my files retained on your server?
No. We write your PDF to a temp directory, run Ghostscript, return the compressed bytes, and delete the temp directory — all within the same request. The compressed PDF is sent in the response body and not persisted anywhere on our side after the response completes.

Need to combine compressed files?

Compress all your inputs first, then merge them in the browser. The combined output stays small and stays text-searchable.

Try Merge PDF

Related PDF tools

Other tools in the Optimize category — built on the same private, in-browser pipeline.

Use cases for this tool

Step-by-step workflows that put this tool to work.

How to shrink a PDF to fit an email attachment limit
Get a 40 MB scan under Gmail's 25 MB or Outlook's ~20 MB cap — without it turning to mush.
How to split one big PDF into separate documents
Turn a single scanned stack into clean, individually-named files — in your browser, nothing uploaded.
How to build a new-hire onboarding pack as one PDF
Combine your handbook, policies, and forms into one clean, fillable onboarding PDF.
How to turn a slide deck PDF into a printable handout
Put 2, 4, or 6 slides per page, number them, and shrink the file for clean printing or sharing.
How to rotate and straighten a scanned PDF
Fix sideways or upside-down scans and trim the messy edges — in your browser, nothing uploaded.
How to convert a PDF to grayscale for cheaper printing
Strip the colour so a print run uses black toner instead of expensive colour ink.
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