Drag and drop a PDF file here
How to use
- Open the PDF you want to shrink. Its current file size is shown.
- Pick a compression level. Start with Balanced; choose Strong if the result is still too big, or Light if you need sharper images.
- If a text-heavy PDF barely shrinks, turn on the option to convert whole pages to images.
- Press Compress PDF to see the size reduction and download the result.
Why PDFs get large
Images account for most of a PDF’s size. Text is stored as font data and character codes, so even a long report rarely exceeds a few hundred kilobytes, but a single phone photo can add 3–5 MB. Scanning in color at 300 dpi or more, or combining a stack of photos into one PDF, quickly produces files of tens of megabytes. Screens and office printers do not need that much detail, so resizing images to a sensible resolution cuts the file size dramatically with little visible difference.
Two ways to compress
Recompress images (when supported): The tool finds the photos and scanned images inside the PDF, lowers their resolution to a sensible level and saves them again as JPEG. Text, tables and lines are not touched, so selecting, copying and searching work exactly as before. Any image that does not get at least 10% smaller is left as it was. Images that could change color or shape when re-encoded, such as CMYK print images or 1-bit black-and-white scans, are also skipped.
Convert whole pages to images: Each page is rendered as a picture, saved as JPEG and placed into a new PDF. This shrinks files whose size comes from text, fonts or complex drawings too, but text in the result is part of an image and can no longer be selected or searched. It suits documents you only need to submit or share for reading.
If your browser cannot recompress embedded images, the tool selects whole-page conversion and explains this beside the option.
Choosing a level
| Level | Longest image side | Whole-page resolution | Good for |
|---|---|---|---|
| Light | 2,400 px | 150 dpi | Documents you will print, scans with small print |
| Balanced | 1,800 px | 120 dpi | Email attachments, online forms |
| Strong | 1,200 px | 96 dpi | Tight upload limits, screen-only reading |
For an image that fills an A4 or Letter page, 1,800 pixels is roughly 150 dpi, which is comfortable on screen and hard to tell apart from the original on an office printer.
How it works
When image recompression is available, the PDF is opened in a background worker. Each image object is decoded, resized with the browser’s own image engine and written back in the same place. The page structure, bookmarks and links are kept. Whole-page conversion draws each page with pdf.js, the engine used by Firefox’s PDF viewer, and places the picture into a new page of the original size.
Privacy
Everything happens on your device and the PDF is never uploaded. Most online compressors send your file to a server for processing; if the document contains personal details, account numbers or signatures, a tool that works locally is the safer choice. Speed depends on your device, so large files are best handled on a computer.
Frequently asked questions
- How much smaller will my PDF get?
- It depends on what is inside. PDFs built from phone photos or high-resolution scans often shrink to half their size or less. PDFs exported straight from a word processor are mostly text and are already small, so they barely change.
- Will compression make text blurry?
- Recompressing embedded images leaves the PDF's text selectable and searchable. Converting whole pages to images turns text into pixels, which may look softer and can no longer be copied or searched. The tool uses whole-page conversion automatically if your browser cannot recompress embedded images.
- What if the result is bigger than the original?
- If compression does not make the file smaller, nothing is downloaded and the tool tells you so. The file is already well optimized, so keep the original.
- How do I get under an upload limit such as 10 MB?
- Try Balanced first, then Strong. If it is still too large, turn on the whole-page option, or use the Split PDF tool to send the document in two parts.
- Is my PDF uploaded?
- No. Compression runs in your browser and the file never leaves your device, which makes it safe for contracts, tax forms and ID documents.
- Can I compress a password-protected PDF?
- No. An encrypted PDF cannot be read without its password. Remove the password in the program that created it, then try again.