How to Compress a PDF Online
Almost everyone hits the same wall eventually: the attachment is too large to email, the upload portal caps files at 2 MB, or a scanned document balloons to 40 MB for reasons nobody can explain. Compressing a PDF fixes it in seconds. This free PDF compressor offers four quality levels, shows you the exact savings, and processes everything inside your browser — so contracts, ID scans and financial statements never travel to anyone else's server.
Upload your PDF
Drop any PDF file. The page count appears instantly - your document is read locally and never sent anywhere.
Pick a compression level
Choose Light for the best quality, Recommended for a balance, or Strong and Extreme when you need the smallest possible file.
Download the smaller PDF
See exactly how much you saved, then download. Not small enough? Re-compress at a stronger level without re-uploading.
Why Are PDFs So Large in the First Place?
A PDF is a container, and what goes inside it determines the size. A ten-page text document might weigh 200 KB; a ten-page scan of the same document can easily be 30 MB. The difference is images. Scanners and phone camera apps store each page as a full-resolution photograph, often at 300 DPI or higher in a lossless or lightly compressed format — and those photographs dominate the file.
Embedded fonts, high-resolution logos, unused metadata and layered graphics from design tools all add weight too. The PDF specification was designed to preserve everything faithfully, not to be small, which is exactly why a compression step is so often necessary before sharing.
This tool works by re-rendering every page at an optimized resolution and re-encoding it with efficient JPEG compression, then rebuilding the PDF at its original page dimensions. Scanned documents typically shrink 70-90%. Text-based PDFs shrink less, because they were already efficient — and their text becomes a picture, so choose accordingly.
Which Compression Level Should You Choose?
| Level | Typical Savings | Best For |
|---|---|---|
| Light | 40-60% | Documents that may be printed, detailed scans, archival copies |
| Recommended | 60-80% | Email attachments, portal uploads, everyday sharing |
| Strong | 75-88% | Tight upload limits, screen-only viewing, WhatsApp sharing |
| Extreme | 85-95% | Very strict size caps where readability matters more than sharpness |
Common Situations This Tool Solves
Attachment too large to email
Gmail and most providers cap attachments around 25 MB, and corporate mail servers often far lower. Compress at Recommended level and a 40 MB scan usually lands comfortably under 10 MB with no visible difference on screen.
Upload portal rejects your file
Government forms, visa applications, university systems and job portals frequently enforce 1-2 MB limits. Strong or Extreme level gets almost any scanned document under those caps.
Phone scans that are absurdly large
Scanner apps save each page as a high-resolution photo, so a five-page scan can hit 30 MB. This tool re-encodes those page images efficiently, typically cutting 80% or more without changing how the document looks.
Storing or sharing many documents
Compressing a folder of PDFs before archiving or sending saves storage, upload time and bandwidth - especially useful on slow connections or limited mobile data.
Frequently Asked Questions
How much can a PDF be compressed?
Scanned documents typically shrink 70-90% because their page images are re-encoded efficiently. Text-based PDFs that were already optimized shrink far less. The tool shows your exact savings after compressing, and you can try a stronger level instantly.
Will compressing reduce the quality of my PDF?
At Light and Recommended levels the document looks essentially identical on screen. Stronger levels trade visible sharpness for size. Use Light if the file will be printed, and Strong or Extreme only when you must hit a strict size limit.
Will my text still be selectable after compression?
No. This compressor re-renders pages as optimized images, which is what makes the file dramatically smaller. The output is a picture of each page, so text is no longer selectable or searchable. If you need selectable text, keep the original file.
Is it safe to compress confidential PDFs here?
Yes, and this is the main reason to use this tool. Your PDF is processed entirely inside your browser. It is never uploaded to any server, never stored, and never seen by anyone - unlike most compressors, which require an upload.
How do I compress a PDF to under 1 MB or 2 MB?
Start at Recommended and check the resulting size shown on screen. If it is still too large, click Re-compress at Strong or Extreme - no need to upload the file again. Very long documents may also need to be split first.
Is there a file size limit?
No fixed limit. Because compression runs on your own device, the practical ceiling is your available memory. Very large documents simply take a little longer to process.
Why did my PDF barely get smaller?
Your file was probably already well optimized - a text-only PDF exported from Word, for example, has very little to compress. In that case the tool will tell you so rather than pretending to save space it cannot save.
Can I compress a password-protected PDF?
Encrypted PDFs cannot be read without their password. Open the file in your PDF reader, remove the protection, save it, then compress the unlocked version here.
How do I compress a PDF on iPhone or Android?
Open this page in Safari or Chrome, tap the upload area, choose a PDF from your Files app, pick a compression level, and download the smaller file directly to your phone. No app installation needed.
Does compressing change the page size or dimensions?
No. Pages keep their original dimensions, so an A4 document stays A4 and prints at the correct physical size. Only the internal image resolution and encoding change.
Should I compress before or after merging PDFs?
Merge first, then compress the combined file once. Compressing each part separately and then merging gives a slightly larger result and takes longer.
Is this PDF compressor really free?
Completely free, with no file size limits, no watermarks, no signup and no premium wall. Because everything runs in your browser, there are no server costs for us to pass on to you.
Last updated: July 11, 2026 · FlipMyFormat PDF Compressor
Written and maintained by the FlipMyFormat team