Are my PDF files uploaded to a server?

No. All compression happens entirely inside your browser using JavaScript. Your files never leave your device and are never sent to any server.

What is the difference between the compression presets?

Screen/Web applies aggressive compression for small file size, ideal for email or web sharing. Standard is a balanced choice for everyday use. Print preserves more quality for office printing. High Quality applies minimal compression for archiving. Lossless only applies structural optimisation without re-encoding images.

Will compressing a PDF make text unreadable?

At lower presets (Screen, Standard), the PDF is rasterised — text becomes an image and is no longer selectable. At Print, High Quality and Lossless presets, text sharpness is well preserved. A warning is shown for presets that rasterise content.

What is metadata stripping?

PDF files often contain hidden metadata including the author name, software used, creation date and keywords. Stripping this removes the information and slightly reduces file size.

Compress PDF Online — Free & Instant

Q: Can I compress multiple PDFs at once?

Yes. You can upload multiple PDF files at once. Each file gets its own compression card with individual progress, size comparison and download button.

Reduce PDF file size by up to 90% with 5 quality presets. Batch compress multiple files, see before/after size savings, and download instantly.

Up to 90% reduction Batch multiple files 5 quality presets No sign-up Files stay private

Drop PDF files here

or click to browse — multiple files supported

PDF

Compression preset

Note: This preset re-renders pages as images — text will no longer be selectable in the output PDF. Use Print, High Quality or Lossless to preserve text selection.

GrayscaleConvert to black & white

Strip metadataRemove author, creator info

Output name: e.g. "Invoice" → Invoice-compressed.pdf

Presets

90%

Max reduction

∞

Files at once

Free

Always & forever

HOW IT WORKS

How to Compress a PDF Online

Reduce your PDF file size in three steps — no software, no sign-up.

Upload your PDFs

Drop one or more PDFs onto the upload area or click to browse. You can compress multiple files in one go.

Choose a preset

Pick Screen for maximum compression, Standard for everyday use, Print for office quality, or Lossless to keep text selectable.

Download & compare

See the before/after size reduction for each file, preview quality, and download individually or all as a ZIP.

PRESETS

Which Preset Should I Choose?

Each preset balances file size against quality for a different use case.

Preset	Resolution	Image quality	Typical reduction	Best for	Text selectable?
📱 Screen / Web	72 DPI	60%	60–90%	Email, WhatsApp, web uploads	❌ No
⚖️ Standard Recommended	96 DPI	75%	40–70%	Everyday sharing & storage	❌ No
🖨️ Print	150 DPI	85%	25–45%	Office printing, reports	❌ No
🏆 High Quality	200 DPI	92%	10–25%	Archiving, legal documents	❌ No
🔒 Lossless Only	Original	Original	5–15%	When text selection is required	✅ Yes

FEATURES

Why Use PrimeSEOTools to Compress PDFs?

Built for real compression — not just metadata stripping like most free tools.

100% Private

All compression happens in your browser. Files are never uploaded to any server or seen by anyone.

Real Compression

Unlike basic tools, we re-render pages at your chosen quality — achieving up to 90% reduction on image-heavy PDFs.

Before/After Comparison

See the exact size reduction and a visual side-by-side preview of each page before you download.

Batch Processing

Compress multiple PDF files in one go. Each file gets its own progress bar, size comparison and download button.

Instant Processing

No upload queue, no server wait. Compression runs on your CPU — results are ready in seconds.

Always Free

No subscriptions, no daily limits, no watermarks added. Every preset and every file is completely free.

Common Reasons to Compress a PDF

Reduce size to send by email

Share on WhatsApp or Telegram

Upload to a web form with file size limit

Save storage on phone or cloud drive

Faster loading for a PDF on a website

Shrink scanned documents

Reduce invoice or report file size

Batch compress a folder of PDFs

FAQ

Frequently Asked Questions

Everything you need to know about compressing PDFs online.

How much can this tool compress a PDF?

Depending on the preset and content, compression can reduce file size by 20% to 90%. Image-heavy PDFs see the biggest reductions. PDFs that are already optimised may see smaller gains.

Are my files uploaded to a server?

No. All compression happens entirely inside your browser using JavaScript. Your files are never sent to any server, never stored in the cloud, and never seen by anyone.

What is the difference between the presets?

Screen/Web gives maximum file size reduction at 72 DPI — ideal for email or web. Standard is the best balance for everyday use. Print preserves office printing quality. High Quality applies minimal compression for archiving. Lossless only applies structural optimisation without re-encoding images, preserving text selection.

Will compressing make text unreadable?

At Screen, Standard and Print presets, pages are re-rendered as images — text remains readable but is no longer selectable or searchable. At High Quality the difference is minimal. Choose Lossless Only if you need to preserve text selection entirely.

Can I compress multiple PDFs at once?

Yes. Upload multiple PDFs at once. Each file gets its own compression card with individual progress, before/after size comparison, and download button. You can also download all compressed files as a single ZIP.

Can I compress a PDF on my phone?

Yes. The tool works on all modern mobile browsers including Safari on iPhone and iPad, and Chrome on Android. No app download needed.

What does the grayscale option do?

Converting to greyscale removes all colour information from the PDF, which significantly reduces file size for colour-heavy documents. The output is a black-and-white PDF — useful for documents where colour is not needed.

How do I compress a password-protected PDF?

Remove the password first using our Unlock PDF tool, then return here to compress the file.