📎 PDF Tools

Compress PDF — Reduce File Size, Free & Private

Shrink a large PDF down to a fraction of its size, right in your browser. Pick a quality preset, compress, and see exactly how much smaller it gets before you download.

✓ Free forever✓ No upload✓ No signup✓ 3 quality presets

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Drop a PDF file here

or click to browse · One PDF at a time

Loading PDF engine…

✅

Compression complete!

⬇ Download

Quick answer: Reduce a PDF's file size by choosing Low, Medium, or High quality — 100% free, browser-based, no file upload required. Convertlo rebuilds the PDF at your chosen quality and shows you the size reduction before download.

How to Compress a PDF

Upload Your PDF

Drop your PDF onto the tool, or click to browse and select it.

Pick a Quality Preset

Choose Low for the smallest file, Medium for everyday sharing, or High to keep more detail.

Click Compress

Convertlo rebuilds your PDF at the new size, entirely in your browser.

Download

Check the size reduction, then download your compressed PDF.

Why Use Convertlo to Compress PDFs?

🔒 100% Private — files never leave your browser, zero server uploads
🆓 Free forever — no account, no watermark, no file size cap per session
🗜️ 3 quality presets — Low, Medium, High to match your needs
📉 See the reduction — original vs. compressed size shown before download
📱 Works on mobile — works on any device with a modern browser
⚡ No queue, no wait — processing starts the instant you click Compress

Features

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100% Private

No server. No upload. Your PDF stays on your device the whole time.

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Low Preset

Maximum compression for the smallest possible file.

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Medium Preset

Balanced quality and size for everyday sharing.

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High Preset

Keeps more detail while still reducing file size.

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Size Comparison

See exactly how much smaller your PDF gets.

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Mobile-Ready

Works on iPhone, Android, tablet, and desktop.

Frequently Asked Questions

Yes — completely free, no limits, no watermarks, no account required. Convertlo runs entirely in your browser.

No. All compression happens locally in your browser using pdf.js and pdf-lib. Your files never leave your device.

Convertlo renders each page of your PDF to an image at your chosen quality, then rebuilds a new PDF from those images at a reduced size. This works especially well for scanned documents and image-heavy PDFs.

No. Because each page is re-rendered as an image, the compressed PDF will look the same but the text will no longer be selectable or searchable. If you need to keep selectable text, don't compress — just merge or split instead.

Use High for documents you'll print or zoom into, Medium for general sharing and email attachments, and Low for the smallest possible file size when quality matters less, like web uploads or quick previews.

Password-protected PDFs cannot be compressed. Remove the password first using Preview on Mac or Adobe Reader, then compress here.