Compress PDF Free Online

Shrink a PDF for email, WhatsApp or portal uploads. Three presets — from smallest file to best quality.

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What is the Compress PDF tool?

The Compress PDF tool reduces file size by re-rendering each page as an optimized image and rebuilding the PDF, right on your device. Three honest presets let you choose the trade-off: Strong for the smallest file (great for email limits), Recommended for everyday sharing, and Light when quality matters most. You see the before/after size the moment it finishes.

Key features

  • Three presets: Strong (smallest), Recommended, Light (best quality)
  • Shows the original and compressed file sizes after processing
  • Useful when an email or upload form has a file-size limit
  • Handles scanned documents and photo-heavy PDFs especially well
  • Processed entirely on your device — no upload

How do I use it?

  1. Drop the PDF you want to shrink.
  2. Pick a compression level — Recommended works for most cases.
  3. Click Compress & download.
  4. Check the size result shown (original → new); re-run with Strong if you need it smaller.

Is it safe to compress a PDF online?

Yes. Pages are rasterised with Mozilla’s PDF.js and rebuilt into a new PDF using only your device’s processor and memory. Note one honest trade-off: because pages become images, text in the compressed copy is no longer selectable — keep your original for editing and use the compressed copy for sharing.

Tips for the best result

  • For a strict upload limit, start with Strong and check the actual output size before submitting.
  • Text-only PDFs are already small; compression helps most on scans and photos.
  • Keep the original file — compression is one-way since pages become images.
  • If the result looks soft, re-run the original with Light instead.

Choose the right PDF compression level

Recommended is a practical starting point for everyday sharing. Use Strong when file size matters more than image detail, and Light when preserving visual quality is the priority. After compression, compare the downloaded PDF with the original before sending or uploading it.

Worked example: getting a scan under a portal limit

Say a college portal accepts PDFs up to 1 MB, and your six-page scanned mark sheet bundle is 4.8 MB. Start with the middle preset and check the size the tool shows. If it is still above the limit, try Strong. Then open the result and zoom in on the smallest text, such as roll numbers and dates. If those are readable, upload it. If not, remove a page you do not need or scan again in better light, because a sharper source compresses more cleanly.

Frequently asked questions

How much smaller will my PDF get?

Photo-heavy and scanned PDFs often have more room to shrink than text-only PDFs. The final reduction depends on the document, so compare the before/after size shown by the tool. A phone scan usually shrinks far more than a typed report, because scans are made of large images.

Why is my compressed PDF's text not selectable?

Compression rebuilds pages as optimized images — that’s what makes the file dramatically smaller. Keep the original if you need editable text.

Can I compress a PDF to under 2 MB or 500 KB?

It may be possible, depending on the source file and page count. Use the Strong preset when you need a smaller result, then check the exact size shown by the tool. If the strongest preset is still too large, remove pages the recipient does not need with Delete Pages, or split the PDF and send it in parts.

Does compressing work on scanned documents?

Yes — scans compress best of all, because their large embedded images have the most room to optimize. Check that small print and signatures are still readable after compressing, especially on ID cards and certificates.

Is there a size limit for the file I compress?

No fixed limit. Large files just take a little longer since your own device does the work. On a phone, a very large file may need a laptop instead, because the work happens in your device’s memory.

Is my document uploaded to compress it?

No. The whole process runs in your browser; the file never leaves your device. That makes it suitable for bank statements, ID proofs and contracts you would not want to send to an unknown server.

Can I compress the images in a PDF?

Yes. Compression mainly reduces the size of images inside the PDF; Strong gives the smallest file, Light keeps the most detail.

Related tools: Merge PDF · PDF to JPG · Split PDF · PDF quality and file size guide

Reduce PDF size for an email attachment or upload limit, then inspect small text in the downloaded copy. The smallest preset is not always the best choice for scanned handwriting.

🔒 Privacy: this tool runs entirely in your browser. Your file is never uploaded, stored, or shared. LyfPDF offers 33 free PDF tools, including 12 core tools localized in 7 languages, with 0 uploads — learn how it works.