Compress PDF Online

Rebuild a PDF's internal structure and compare the saved size with the original – free, private and mobile-friendly.

📖 Read the full guide →

Tool status: This version rebuilds the PDF structure. It does not down-sample images, so scanned or photo-heavy files may not get noticeably smaller.
📉

Select PDF file

or drag & drop PDF here

🔒 Processed 100% in your browser — your file is never uploaded to a server

Continue with:Image to PDF & PDF Size ToolsImage to PDFJPG to PDF Under 100 KB

About Compress PDF

Quick answer

Compress PDF aims to reduce document size so it is easier to store or send. Select the PDF, choose an available compression preset, process it, and compare the downloaded size.

iLikePDF's Compress PDF tool lets you rebuild a PDF's internal structure and compare the saved size with the original – free and without any software. It is a good fit for tidy a PDF that was exported with redundant structure, try a quick size reduction before attempting a heavier workflow and prepare a file for an email limit when it is already close. You may also know it as compress pdf online, free compress pdf.

Everything happens in your browser: your files are not uploaded to our servers. It is private by design, quick to use and mobile-friendly. This version is limited, so read the notice above the tool.

Full walkthrough: Why Your Compressed PDF Is Still Too Large (and What to Try)

Conceptual illustration of the Compress PDF workflow: select a file, set options and download the result
Compress PDF: conceptual illustration of the workflow, not a screenshot.

How to Use Compress PDF

  1. Choose the PDF and note its size in your file manager.
  2. Select Compress PDF File. The tool rebuilds the file and downloads compressed-name.pdf.
  3. Compare the new size with the original and keep the smaller of the two.
  4. If the result is still too large, follow the reduction workflow in the compression guide (lower-resolution images before building the PDF, or splitting the file).

Before & After

Before using Compress PDF - your original file(s)

Before (Your original file(s))

  • Files as you have them
  • Nothing has been changed yet
After using Compress PDF - new result file

After (New result file)

  • A new file downloads to your device
  • Your original stays untouched

Conceptual illustration, not a screenshot.

Supported Input and Output

Compress PDF Features

  • ✅ 100% free – no payment, no sign-up, no watermark.
  • ✅ No software – compress pdf online straight in your browser.
  • ✅ Private by design – your file is processed on your device, not uploaded to our servers.
  • ✅ Original kept – a new file is created.
  • ✅ Works on mobile and desktop – Android, iPhone, Windows and Mac.
  • ⚠️ Limited version – read the notice above the tool to see exactly what it does today.

Who Should Use Compress PDF?

  • Students – Send scanned notes and assignments as one PDF that fits an email or portal limit.
  • Job Seekers – Create a resume or certificate PDF under the size a job portal allows.
  • Professionals – Email lightweight reports, quotes and invoices.
  • Small Businesses – Share catalogues and bills as small PDFs on WhatsApp.
  • General Users – Store ID and document copies as compact PDFs.

Use Cases and Output Checks

Common uses

  • Tidy a PDF that was exported with redundant structure.
  • Try a quick size reduction before attempting a heavier workflow.
  • Prepare a file for an email limit when it is already close.

Check the output

  • Compare the new file size with the original.
  • Open the result and check that text, images and links still look right.
  • Confirm that forms and fields you need still work.

Limitations and Troubleshooting

  • This is structural optimisation, not image compression. Scans and photo-heavy PDFs may not get smaller.
  • There is no quality slider or target-size control.
  • Encrypted or damaged PDFs cannot be opened.

Common problems

Accepted inputOne PDF file (.pdf).
OutputA rebuilt PDF named compressed-.pdf.
What it changesPages are copied into a new document and saved with object streams. Embedded images are not re-sampled and fonts are not removed.
Expected savingsVaries. Files with unused objects or repeated structure may shrink; image-heavy scans usually change very little, and a file can even stay the same size.
File handlingThe processing code runs in your browser. The page loads the pdf-lib library from the unpkg CDN when it opens; the tool code does not send your PDF to a server.
ProblemWhat to try
The file did not get smallerThe size is dominated by images. Reduce image size before creating the PDF, or split the document into parts.
The result is slightly largerKeep the original; a rebuild does not always help.
Tool groupImage to PDF & PDF Size ToolsMore toolsImage to PDFMore toolsJPG to PDF Under 100 KBMore toolsCompress PDF to 100 KBToolSplit PDFToolJPG to PDFToolOCR PDFGuideWhy Your Compressed PDF Is Still Too Large (and What to Try)GuideHow to Reduce PDF File Size and Keep Text Readable

Quick Summary

FeatureDetails
Tool nameCompress PDF
Cost100% free
Software requiredNo
File uploadNo – processed in your browser
Supported devicesMobile & desktop
Best forTidy a PDF that was exported with redundant structure

Share This Tool

If you found this tool useful, share it with friends and classmates:

Disclaimer

Compress PDF is for personal and educational use. Check your local laws and your organisation's rules before you process copyrighted or sensitive documents. Results depend on your file and browser, so always check the output before you use it. This version of the tool is limited; see the notice above the tool.

FAQs – Compress PDF

1. Compress PDF kaise use karein?

Apni file select karein, settings check karein aur “Compress PDF File” button dabayein. Result neeche dikhega; phir Download par tap karein.

2. Kya Compress PDF free hai?

Haan, iLikePDF ka Compress PDF tool bilkul free hai. Koi payment ya signup nahi chahiye.

3. Kya main mobile se Compress PDF use kar sakta hoon?

Haan, yeh tool mobile-friendly hai. Aap Android ya iPhone ke browser se bhi Compress PDF use kar sakte hain.

4. Kya meri file upload hoti hai?

Nahi. Yeh tool aapke browser me chalta hai; aapki file iLikePDF ke server par upload nahi hoti. (Kuch features ek helper library CDN se load karte hain, lekin aapki file unme nahi jaati.)

5. What does Compress PDF do?

Compress PDF aims to reduce document size so it is easier to store or send. Use it when the required result matches this operation; keep a separate copy of the source.

6. How do I use Compress PDF online?

Select the PDF, choose an available compression preset, process it, and compare the downloaded size. Open the downloaded result before sending it to someone else.

7. Which source should I prepare for Compress PDF?

Prepare a readable PDF and note its current size. Start with a file that opens correctly in its usual viewer. A renamed extension does not convert the underlying format.

8. What should I check in the Compress PDF output?

Check text clarity, photographs, diagrams, searchable text and the final byte size. Keep the original until the result has passed these checks.

9. Can every PDF be compressed below 100 KB?

No. The achievable size depends on page count, image detail and the starting encoding. Remove unneeded pages or revise the source if compression alone cannot meet the limit.

10. Why did my PDF barely shrink?

It may already be optimized or contain mostly compact text and vectors. Repeated compression is unlikely to create a large improvement in that case.

11. Can compression make a PDF larger?

Yes, rewriting or re-encoding may increase some files. Compare both outputs and retain the smaller version that still meets your quality needs.

12. Does compression always preserve quality?

No. Downsampling and lossy image compression can reduce detail. Start with a moderate preset and inspect small text before using stronger settings.

13. Which compression preset should I choose?

Start with the least aggressive setting that meets the size requirement. Stronger compression is useful only if the result remains readable for its purpose.

14. Will text remain selectable?

That depends on the compression method. Check selection and search after processing, especially if the implementation renders entire pages as images.

15. Should I compress before or after merging?

For one final attachment, merging first lets you measure the finished bundle. If memory is a problem, carefully optimize source copies before merging.

16. How do I verify a portal’s size limit?

Read its accepted format and maximum size, then inspect the saved file’s properties. Keep a little room below the cap because size units and validation can differ.

17. Why might Compress PDF fail on a large file?

A high-resolution scan may use considerable memory while its pages are processed. Close unnecessary tabs and test a smaller non-confidential sample to separate a file-specific problem from a browser problem.

18. When is Compress PDF useful?

Prepare email attachments or documents for a portal with a maximum file size. Confirm the recipient’s requirements before preparing the final version.

19. What can I do after using Compress PDF?

Related next steps include Split PDF, JPG to PDF, OCR PDF. Choose one only when you need that additional operation. Review the a size-optimized PDF before applying another change, and retain your source copy.