Compress PDF Files
Without Losing Quality
Reduce your PDF file size with smart compression. Choose your quality level and get instant results — completely free and private.
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Browse FilesWhat Is PDF Compression?
PDF compression is the process of reducing the file size of a PDF document so it takes up less storage space and is easier to email, upload, or share. Smaller files also load faster in viewers and use less bandwidth. Compression works by lowering the resolution or quality of images inside the PDF and by removing redundant data, while keeping text and layout readable.
Many PDFs become large because they contain high-resolution images, embedded fonts, or unoptimized graphics. A compressor re-encodes these elements so the file shrinks without losing so much quality that the document becomes unusable. The result is a balance between file size and how good the PDF looks on screen or in print.
Our online PDF compressor processes everything on your device. You pick a compression level (e.g. maximum, balanced, or best quality), and we handle the file privately. Your document never gets uploaded to our servers, so your data stays private. After compression, you see the original size, new size, and percentage reduction, then download the compressed PDF.
Unlike desktop software that requires installation and often a paid license, our compressor works on any device — Windows, Mac, Linux, Chromebook, or even a tablet. There is nothing to download, no account to create, and no limit on how many files you can compress. You stay in full control of the trade-off between size and quality.
Discover Features of Our PDF Compression Tool
Reduce PDF file size with a secure, fast, and intuitive compression experience
Three Compression Levels
Choose Low for maximum size reduction when file size matters most, Medium for a balanced trade-off between size and quality, or High to preserve visual quality while still shrinking the file. Each level re-encodes images and streamlines the PDF so you get predictable results for email, uploads, or archiving.
Size and Savings Display
After compression completes, the tool shows the original file size, the new compressed size, and the percentage reduction. You can see exactly how much space you saved and decide whether to try a different level if you need a smaller file or better quality.
100% Private & Secure
All compression happens on your device. Your PDF is never sent anywhere, so sensitive documents stay private. Once you're done, no copy of your file remains anywhere. Ideal for work documents, tax files, or personal records.
Page-by-Page Progress
A progress indicator shows which page is currently being processed, so you know the tool is working even on long documents. There is no guessing whether the process has stalled — you see real-time feedback from start to finish.
No Sign-Up or Limits
Use the compressor immediately without creating an account. There are no watermarks, no trial limits, and no payment required. Compress as many PDFs as you need, for personal or commercial use, with no strings attached.
Works on Any Device
No desktop software or installation required. The compressor works on Windows, macOS, Linux, tablets, and phones. Open the page, add your PDF, choose a level, and download the compressed file from any device.
Steps to Compress a PDF
Reduce PDF file size in four simple steps — no sign-up required
Select Your PDF File
Drag and drop a single PDF into the upload zone, or click to browse your device. Only PDFs are accepted. The file name and size are shown so you can confirm you have chosen the right document.
Choose Compression Level
Select Low (maximum compression), Medium (balanced), or High (best quality). Low gives the smallest file with more visible quality loss; High keeps quality closer to the original with a smaller size reduction.
Click Compress PDF
Start compression. The progress indicator shows which page is being processed. For long documents this may take a short while — everything happens privately on your device.
Download the Compressed File
When done, the compressed PDF downloads automatically. You will see the original size, new size, and percentage saved. Use the file for email, uploads, or archiving; your original file is left unchanged.
Free vs Paid — Compress PDF
Get started free, upgrade when you need more power.
Unlock the Full Power of Compress PDF
Remove daily limits, process larger files up to 500 MB, enable batch processing, and get priority support.
PDF Tools includes:
- 21 PDF tools included
- Unlimited daily uses
- 100 MB file size limit
- Batch processing
- Sign, Redact, OCR, Watermark
- All export formats
Also available in the All Tools Bundle
Our Users' Questions & Reviews
Verified questions from real users and expert answers from the OnlinePCTools team
“I need to email a 28 MB report but my provider has a 25 MB limit. Will compressing the PDF actually get it under the limit?”
Sarah Mitchell
Project Manager, London, UK
In most cases, yes. PDFs that are large due to high-resolution images or unoptimized graphics compress well. Choose the Medium or Low level to maximize size reduction. After compression, the tool shows the new file size and percentage saved, so you will know immediately if you are under 25 MB. If you are still over, try Low compression or consider splitting the report and sending it in two emails using our Split PDF tool.
— OnlinePCTools Team
“I have sensitive client contracts. Is it safe to use an online compressor or will my files be stored on your servers?”
James Okonkwo
Legal Assistant, Lagos, Nigeria
Your files are never uploaded or stored. The entire compression process happens on your device. Your PDF is read, re-encoded, and written privately. We have no external processing for your document content. Once you're done, nothing remains. Your data stays completely safe and private.
— OnlinePCTools Team
“Will compressing my PDF make the text and images look blurry or unreadable when I print it?”
Elena Vasquez
Teacher, Madrid, Spain
It depends on the level you choose. High compression keeps quality close to the original and is usually fine for printing and detailed viewing. Medium is a good balance for screen viewing and light printing. Low compression reduces size the most and can make images or very fine text slightly less sharp, so use it when you need the smallest file and print quality is less critical. For important printouts, we recommend starting with High or Medium and checking the result before sending.
— OnlinePCTools Team
“Can I compress a password-protected PDF, or do I need to remove the password first?”
Wei Zhang
IT Administrator, Singapore
Password-protected PDFs must be unlocked before compression. The compressor cannot read or modify locked files. Use our PDF Unlocker tool first: open the locked PDF there, enter the password, and download the unlocked version. Then run the unlocked file through the compressor. Your documents still never leave your device — both tools process everything privately.
— OnlinePCTools Team
Who Needs a PDF Compressor?
Common scenarios where compressing PDFs saves space and simplifies sharing
Email Attachments
Shrink PDFs so they stay under your email provider’s size limit. Recipients can download them quickly without timeouts, and you avoid “file too large” bounce-backs when sending reports, proposals, or forms.
Website and Form Uploads
Meet strict file-size limits on job portals, application forms, scholarship systems, or document upload pages. Compress the PDF first so it fits the limit while remaining readable and professional.
Backup and Storage
Keep archives of invoices, reports, or scanned documents in smaller files. You use less disk space, backups run faster, and cloud storage quotas go further without losing essential content.
Sharing and Collaboration
Send proposals, drafts, or handouts via chat or cloud storage with smaller files. Teammates can open them quickly on any device, and you avoid hitting attachment or upload limits in collaboration tools.
Mobile and Slow Connections
Reduce file size so PDFs load faster on phones and in areas with limited bandwidth. Recipients on mobile or slow networks can view and download the file without long waits or failed loads.
Scanned Document Archives
Scanned PDFs are often very large. Compress them for long-term archiving or sharing while keeping text and images readable. Ideal for digitized records, receipts, and legacy document storage.
Frequently Asked Questions
Common queries and answers about the PDF Compress Tool
Q1. Is PDF compression free?
Q2. Are my PDFs uploaded to your servers?
Q3. Will compression reduce quality?
Q4. What is the maximum file size I can compress?
Q5. Can I compress password-protected PDFs?
Q6. Do I need to install anything?
Q7. Which compression level should I choose for printing?
Q8. Does the tool work on mobile phones and tablets?
Explore More PDF Tools
Compress your PDFs, then use these tools to merge, split, convert, or secure them further.