Why did my PDF not get much smaller?
This tool rewrites PDF structure and strips metadata but does not recompress embedded images — scanned documents may stay large.
Pdf Tools
Compress a PDF File
Rewrite a PDF with browser-side optimization to reduce file size where possible before email or upload.
What compression actually rewrites
This compressor rebuilds your PDF using pdf-lib's object-stream saving and clears the document's title, author, subject, and keyword metadata. That combination shrinks the file structure itself, which is enough to meaningfully reduce many text-based PDFs — reports, forms, exported documents — without touching the visible page content.
It does not re-compress embedded images. A PDF that is mostly high-resolution scans or photos will see little size change, because the bulk of that file's weight is image data the tool doesn't rewrite. For those files, reducing image quality before the pages are placed into a PDF (or using Compress Image on the source photos) makes a bigger difference than running this tool alone.
Workflow at a glance
Use this quick flow to understand where the tool fits in your work and what to review before relying on the output.
Review checklist
Before
Note the current file size and whether the PDF is mostly text or mostly scanned images — that determines how much this tool can help.
After
Compare the new size against the original and open a few pages, especially tables or signatures, before replacing the source file.
When this compressor helps most
Use it first for any PDF that needs to be smaller — it's a quick, no-cost pass that sometimes solves the problem outright for text-heavy documents, and costs nothing to try even when it doesn't help much on scanned ones.
Who hits PDF size limits
Job and college applicants
Get a generated resume or form PDF under a portal's strict upload size limit.
Office staff emailing documents
Shrink reports or contracts enough to attach without hitting an inbox's size cap.
Anyone archiving old PDFs
Strip unnecessary metadata and rebuild files before storing them long-term.
Developers testing generated PDFs
Check whether a PDF produced by another tool can be optimized without altering the source.
What the rebuild does and doesn't touch
Object-stream rebuild
Saves the PDF using pdf-lib's object-stream format, which is typically more compact than the original structure.
Metadata stripped
Title, author, subject, and keyword fields are cleared as part of the rebuild.
Page content untouched
Text and vector content are preserved as-is — this isn't a lossy recompression of what's on the page.
No image recompression
Embedded photos and scans keep their original resolution, which is why image-heavy PDFs shrink the least.
One click, instant result
Upload, run, and compare the new file size against the original immediately.
Compressing a PDF step by step
- 1Upload the PDF that's too large for your email, form, or portal.
- 2Click Process so the browser rewrites the PDF structure locally.
- 3Compare the downloaded file size with the original.
- 4Open the compressed PDF and check important pages before replacing the original.
Where a smaller PDF matters
Bringing a PDF below a job portal, college portal, or government form's upload limit.
Shrinking invoices, reports, or agreements enough to send as a normal email attachment.
Removing unnecessary metadata before archiving a shared copy.
Testing whether a generated PDF can be optimized without changing the source document.
Where the rebuild happens
The rebuild runs locally using pdf-lib — the PDF is never uploaded to a server. Because metadata is stripped as part of the process, this also happens to remove author and title details you may not want to keep in a shared copy.
Getting a real size reduction
- Try this tool first — it costs nothing and sometimes solves the size problem on its own for text-heavy PDFs.
- If the file is still too large, check whether it contains large embedded photos or scans; that's the size this tool can't touch.
- Compress source images before building a PDF from them, rather than trying to shrink the finished PDF.
- Keep the original file until you've confirmed the compressed version opens correctly.
Compression mistakes to avoid
Expecting scanned PDFs to shrink a lot
Image-heavy PDFs barely change size here, since embedded images aren't recompressed.
Assuming metadata removal is reversible
Title, author, subject, and keywords are cleared during the rebuild — keep the original if you need that metadata later.
Skipping the before/after size check
Always compare file sizes; some PDFs (already efficiently saved) won't shrink further.
Not checking pages after compressing
Open the result and check a few pages, especially any with tables or signatures, before replacing the original.
If it still isn't small enough
Compress PDF is a fast, free first attempt at shrinking a document. When a scanned or photo-heavy PDF doesn't shrink enough, the fix is usually reducing image quality before the PDF is built, not running this tool again on the same file.
Need hands-on help?
Get help with documents, SEO, content, or website fixes
Use this tool for quick work. If you need a real file prepared, a page reviewed, or a website issue fixed, send the URL and describe the problem.
FAQ
Compress PDF FAQ
Answers for using Compress PDF on I Love Tool XYZ.
Does the compressor remove text?
No. Page text and layout are preserved; only the file structure and metadata change.
Should I delete the original after compressing?
Keep the original until you've opened the compressed PDF and confirmed the pages look correct.
Is this enough for strict upload limits?
Sometimes. If the PDF is mostly high-resolution scans, you may need to reduce image quality before rebuilding the PDF.
Is my PDF uploaded anywhere during compression?
No. The rebuild runs locally in your browser using pdf-lib.