Two ways to compress a PDF
PDFs are big for different reasons, so this PDF compressor has two modes. It shows the size before and after, and if a setting would make your file bigger it tells you instead of handing you a worse file.
- Lossless tidy-up: tidies the file and keeps the text selectable. Savings are usually small, but nothing about the pages changes.
- Image compression (High, Medium or Small): redraws each page as an image at the quality you pick. This is what shrinks scanned documents and photo-heavy PDFs. The trade-off is that the text becomes part of the image, so you can no longer select or search it.
How to reduce PDF file size
- Add your PDF.
- Start with Lossless tidy-up and check the new size.
- If the file is still too big and it is a scan or full of images, switch to image compression.
- Pick High for the best quality, Medium for a balance, or Small for the smallest file.
- Compare the before and after size, then download.
What to expect, honestly
A PDF that is mostly text is already small, and it may barely shrink. Redrawing a text PDF as images can even make it bigger, which is why the tool warns you. Compression works best on scanned pages, photos and slide exports.
If you need an email attachment under a size limit and compression is not enough, split the PDF into chunks with Split PDF, or delete pages you do not need.
Choosing between High, Medium and Small
Keep a copy of the original. Image compression cannot be reversed, and once text has become part of an image you cannot copy it again. If you need the words later, convert the page to an image and read it with Screenshot to text, since OCR to a searchable PDF is not available yet.
- High: the sharpest image quality. Good for scans you may print, or pages with small print. The saving is smaller.
- Medium: a sensible default for email and upload forms. Scanned text stays readable on screen.
- Small: the smallest file. Fine for quick sharing, but fine details and small text can look soft.
- Lossless tidy-up: no change to how pages look, text stays selectable. Try this first for PDFs made from Word or other text documents.
Private compression with no limits
iLovePDF, Smallpdf, Sejda, PDF24 and Adobe Acrobat online compress on their servers, so your file is uploaded first. Smallpdf's free plan allows 2 tasks a day and Sejda caps free files at 50 MB.
Here compression runs in your browser. The PDF is never sent to our servers, there is no sign-up, no watermark and no file-size paywall. Very large files depend on your device's memory and can be slow on a phone.
