What this PDF compressor can and cannot shrink
A PDF is a container. Text and fonts usually take little space, while photos and scanned pages take almost all of it. That is why this tool works on the images: it finds every photo and scan in the file, scales it down to the resolution of the level you pick, and stores it again as a JPEG. Text, vector drawings, links, bookmarks and form fields are copied unchanged, so the document still reads, searches and prints the same.
- Shrinks well: scanned documents, photo reports, property listings, brochures with large pictures, slides exported with photos.
- Shrinks a little: PDFs with a few small pictures, or images that were already compressed hard.
- Hardly shrinks: text-only PDFs such as letters, invoices and contracts exported from Word. They are mostly fonts, and those stay as they are.
Charts, logos and screenshots stored without loss are left alone unless they are far larger than needed, so their edges stay crisp. Images the tool cannot read safely, such as print files in CMYK, are kept as they are too. If nothing gets smaller, you are told so and no larger file is created.
The three levels and what dpi means here
Dpi, dots per inch, is the number of image pixels per inch of the printed page. A Letter page scanned at 300 dpi is 2,550 by 3,300 pixels, while a Full HD screen shows 1,920 by 1,080. Low compression keeps images up to 200 dpi at high JPEG quality, Medium goes to 150 dpi, and High to 100 dpi with stronger compression. Images that are already below the level's resolution are not scaled, only saved again if that makes them smaller.
A typical reason to reduce a PDF is an email attachment limit, often around 20 to 25 MB, or an upload form that accepts only a few megabytes. Combining files first? Use Merge PDF and compress the result. To send only some pages, cut them out with Split PDF, and for single pages as pictures, PDF to JPG is often the smaller option.
How to compress a PDF
- 1Drop the PDF on the box. You see its pages, size and how many images it holds.
- 2Pick Low, Medium or High compression and press Compress PDF.
- 3Compare the sizes. If you like the result, download it; if not, try another level. The original is kept.
Frequently asked questions
Is my PDF uploaded?
No. Your browser opens the PDF, recompresses the images in it and writes the new file on your own device. Nothing is sent to a server, so contracts, bank statements and medical letters stay private.
Why did my PDF hardly get smaller?
This tool shrinks the images inside a PDF. A document made of text, like a letter or a report exported from Word, is mostly fonts and text, which are already compact. If the images are small or already compressed well, there is little left to gain, and the tool tells you so instead of handing you a bigger file.
Will the text still be sharp and searchable?
Yes. Text, fonts, vector drawings, links and form fields are copied as they are. Only photos and scanned pages are scaled down and saved again as JPEG, so they lose some detail at high compression, while text stays crisp at any zoom.
Which level should I choose?
Medium is a good start: 150 dpi is sharp on screen and fine for most office printing. Use Low compression for documents you will print in high quality, and High compression for email attachments and upload forms with strict size limits.
Does it work with scanned documents?
Scans are where it helps most, because every page is one big image. A scanner set to 300 dpi or more creates far more pixels than a screen needs. Medium brings those pages to 150 dpi, which usually cuts the file size by more than half.