Compress PDF

Use Compress PDF in a reliable PDF workflow

This compressor renders each page and rebuilds the document with compressed page images. That approach is effective for scans, photographed paperwork and slide decks, but it can make selectable text behave like an image in the output.

When this tool is useful

Choose a lighter setting for email and routine sharing, and a higher-quality setting for diagrams, small print or documents that may be printed. If a PDF is large because it contains unnecessary pages, remove those pages before compression for a cleaner result.

What to check before downloading

Compare small text, signatures, barcodes and fine lines at 100% zoom. Compression cannot guarantee an exact target size because each document contains different images and page dimensions. Keep the original whenever searchability, accessibility or archival quality is required.

Private browser processing and practical limits

Processing runs locally in the current browser tab, so the selected document is not sent to PDF Online Free for editing. Performance depends on the device, available memory, document complexity and browser. Large or unusual PDFs may take longer or may exceed the memory available on a phone. Work on a copy, allow the process to finish before closing the tab, and review the downloaded result before relying on it.

Continue your PDF workflow

A PDF task often needs more than one step. Use the related tools below only after checking the output from the current step; this makes it easier to identify where a change occurred. Organize PDF, Compress PDF, Password Protect PDF and all PDF tools.

Choose compression settings by destination

For an email attachment or a routine preview, begin with a balanced resolution and medium JPEG quality. For contracts, diagrams, forms and pages with small print, use a higher setting and accept a larger result. Aggressive compression is most appropriate for image-only copies where fast sharing matters more than zoomed detail. There is no universal best percentage: the correct setting depends on what the recipient must read and whether the file will be printed.

Why an exact target size cannot be guaranteed

A request such as “compress PDF to 1 MB” sounds precise, but the result depends on page count, dimensions, image detail, colour variation and the quality required for readable text. A ten-page text scan and a ten-page photographic catalogue can need very different settings. The browser can reduce resolution and JPEG quality, but forcing every document below the same threshold could make some pages unreadable. Use the downloaded size as feedback, then repeat with a lighter setting only if the visual comparison remains acceptable.

Searchable text, OCR and accessibility

This compressor rebuilds pages from rendered images. That can reduce file size effectively, but selectable text, links, form controls and the document’s logical reading order may no longer behave like the original. If a scan needs searchable text, run OCR PDF and retain the reviewed text separately. If accessibility, certified signatures or archival preservation matter, keep the original PDF and use an approved specialist workflow rather than replacing it with a rasterized copy.

Reduce size before compression

Compression is not the only way to make a PDF smaller. Remove duplicate or unnecessary pages, crop excessive scanned margins, and avoid inserting camera photos at far higher resolution than the page needs. When creating a PDF from images, resize the source photographs first. These changes often produce a cleaner file than repeatedly lowering image quality.