Free PDF Compressor — Shrink File Size Online
Shrink a PDF's file size right in your browser — recompresses embedded photos, nothing is uploaded.
Drop PDFs here or click to choose
Up to 20 MB per file — compressed entirely in your browser. Files never leave your device.
Compress a PDF so it fits under an email attachment limit or an upload cap, without installing anything or sending your document to a server. The tool works by recompressing the JPEG photos already embedded in the PDF at a quality you choose, then re-saving the file with a more efficient internal structure.
It's most effective on scanned documents and photo-heavy PDFs — the kind where most of the file size is images rather than text. Text-only PDFs (contracts, invoices, forms) will typically see a smaller reduction, since there usually isn't much image data to recompress in the first place.
How to use
- Set the compression level — lower means a smaller file but more visible quality loss in embedded photos.
- Drop your PDF onto the tool or click to choose it.
- Check the before/after file size and how many images were recompressed.
- Download the compressed PDF.
Frequently asked questions
Will compressing reduce the quality of my PDF?
Only the embedded JPEG photos are recompressed, at the quality level you choose — text, vector graphics, and layout are never altered or rasterized. At 60–70% quality, most photos show no visible difference; going lower trades more visible quality loss for a smaller file.
Why did my PDF barely get smaller?
This tool recompresses JPEG images embedded in the file — if your PDF is mostly text (a contract, invoice, or form) there's little image data to shrink, so the reduction will be modest. It works best on scanned documents and PDFs full of photos.
Is my PDF uploaded anywhere?
No. Compression happens entirely in your browser — the file is read, processed, and re-downloaded locally. It never leaves your device, which makes this safe for contracts, IDs, and other sensitive documents.
What's the maximum file size?
20 MB per PDF. Anything larger is rejected with a clear message — this keeps browser-based processing fast and reliable.
Does this work on password-protected PDFs?
Encrypted or password-protected PDFs generally can't be processed by this tool. Remove the password first (in the PDF's original application) if you need to compress a protected file.
Why PDFs get so large
The vast majority of oversized PDFs are large because of embedded images, not text — a single scanned page at high resolution can easily be 1–3 MB, and a 20-page scanned document adds up fast. Text and vector content, by comparison, is extremely compact: a 50-page text-only contract is often under 500 KB.
That's why this tool targets embedded JPEG images specifically — it's where almost all of the recoverable file size actually is. Scanned documents, photo reports, and PDFs exported from presentation software typically see the largest reductions.
Getting a PDF under a specific size limit
• Email attachment limits — most providers cap attachments around 20–25 MB; try 50–60% compression first.
• Government or job application portals — these often cap uploads at 2–5 MB; you may need 30–40% compression, especially on scanned documents.
• If one pass isn't enough, run the compressed output back through the tool at a lower quality — each pass targets the images currently in the file.
Related free tools
- PDF Merge & Split — Combine multiple PDFs into one, or pull pages out of a PDF — free, in your browser, no upload.
- PDF Converter — Turn a PDF into images or text, or combine images into a PDF — free, in your browser, no upload.