Compress a PDF: make it fax-ready and small enough to email
Shrink a PDF by redrawing every page in black and white or grayscale at fax resolution, the way a fax machine will print it anyway. See the size before and after, then download the smaller copy or fax it. Free, no account, and nothing is uploaded: it all happens in your browser on this device.
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Nothing is uploaded. Your files are opened and the new PDF is made by your browser on this device; they are gone when you close the tab.
Drop a PDF here
PDF up to 100 MB and 300 pages
How to use it
- Choose or drop the PDF.
- Pick black and white (smallest, how a fax prints) or grayscale, and a resolution. 200 dpi is fax fine quality.
- Press Compress PDF and compare the size before and after.
- Download the smaller copy, or send it as a fax.
How this works
Everything runs in your browser, with the open-source libraries pdf.js (to read and draw pages) and pdf-lib (to write the PDF). This is what happens to your files.
- Redrawing each page
- pdf.js draws every page at the resolution you chose: 200 dots per inch is the 'fine' mode of a fax machine, 100 dpi is close to its 'standard' mode. A page keeps its size, so it prints as large as before. Very large pages are drawn at a lower resolution so phones don't run out of memory.
- Black and white
- Each pixel becomes black or white: it counts as ink when its brightness is below about two thirds of white, which keeps thin and grey text visible. The page is stored as a 1-bit image with lossless Flate compression, the same kind of picture a fax machine sends. Photos and shading turn into solid black and white areas.
- Grayscale
- Colours are turned into shades of grey and the page is stored as a JPEG. It keeps photos and pencil shading, and is larger than black and white.
- What changes
- The new PDF is a set of page images. Text can no longer be selected, searched or copied, links and form fields are gone, and colour is removed. Keep your original if you need any of those. If the copy comes out larger than your file (common for PDFs that are already small, text-only files), the tool tells you and uses the original.
Questions
Is anything uploaded?
No. The PDF is opened, redrawn and saved by your browser on your device, and is gone when you close the tab. Our analytics record the page count, the settings and the size before and after, never the file or its name. If you choose to fax the result, it is uploaded at that point, on the send page, as part of sending it.
How much smaller will my PDF get?
It depends on the file. Scans and PDFs full of photos usually shrink the most, often to a small fraction of their size in black and white. A PDF that is mostly plain text may already be smaller than any picture of its pages; then the tool says so and keeps your original. You see the size before and after before you download or send anything.
Why black and white for a fax?
A standard fax machine prints in black and white only, so colour and grey are converted on the way anyway. Doing it before sending gives the smallest file and shows you what the recipient will see. Choose grayscale if the document has photos you also want to keep for email.
Will it fit in an email?
Most email services accept attachments up to about 20 to 25 MB (Gmail allows 25 MB, Outlook 20 MB). The tool shows the new size so you can check. For a very long document, 150 or 100 dpi black and white is the smallest.
Can I still edit or search the text afterwards?
No. Every page becomes an image, so the text can no longer be selected or searched and fillable fields are flattened into the page. Keep the original file for editing; use the compressed copy for sending.
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Need to fax it?
Upload your document on the send page, enter the fax number and follow the status until it is delivered. You pay per fax, any number of pages. To check how it will print first, use the fax preview.
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