How to Reduce PDF File Size

Reducing PDF file size is a practical problem with several levers. Which one to pull depends on why your PDF is big: is it full of high-resolution images? Carrying pages you do not need? Built by an old exporter with a bloated structure? This guide walks through each lever so you can pick the right one. Everything happens locally in your browser — your file never leaves your device.

Four ways to shrink a PDF

1. Re-pack the structure — re-save the PDF with object streams so the container shrinks while visible content stays intact. This is what theCompress PDF tool does.
2. Remove unwanted pages — drop blank pages, cover sheets, or appendices you do not need to share. Fewer pages means less data. Use the Remove Pages tool.
3. Split a large document — if you only need to share part of a report, split it into chapters withSplit PDF and send only the relevant part.
4. Regenerate with downscaled images — if the PDF is image-heavy and compression is not enough, re-export from the source application with lower DPI or JPEG quality. This is the most effective lever for scanned documents, but requires access to the source.

Step-by-step: the size-reduction playbook

1. Remove unwanted pages (optional). If the PDF has blank pages or sections you do not need, open/tools/remove-pages/, select the pages to remove, and download the trimmed PDF. This is the fastest way to cut size when you have content you do not need to share.
2. Compress the structure. Open/tools/compress-pdf/, drop in your PDF (or the trimmed version from step 1), and click Run Compress PDF. The tool re-saves with object streams. The results panel shows the original size, compressed size, and reduction percentage.
3. Split if still too large. If the compressed PDF is still bigger than your target (e.g., an email attachment limit), open/tools/split-pdf/ and break it into smaller files. Smaller files travel better over email and chat.
4. Download. Save the smaller PDF — or PDFs — to your device. No upload, no server, no privacy compromise.

What gets smaller with compression?

Object-stream packing compresses the PDF's structural overhead — cross references, dictionaries, and repeated objects. Image and font data that is already compressed will not shrink much further. For image-heavy PDFs, the most effective lever is to regenerate the PDF with downscaled images and a lower DPI from the source application.

Tips for specific cases

• Scanned PDFs are essentially one large image per page. They are often huge because the scans are high-resolution. Re-scan at a sensible DPI (150–200 for text) before compressing — this is the single biggest win for scanned documents.
• Reports with cover pages often carry full-page images or graphics that add bulk. Remove the cover withRemove Pages if you do not need it.
• PDFs with embedded full font sets (including unused glyphs) are larger than necessary. Export with subsetted fonts from the source app when you can.
• Multi-page documents you only share part of — split first, then compress each part. Smaller inputs compress faster.

Common mistakes

• Re-saving as an image-only PDF. Some "compressors" rasterize every page into a JPEG. That can shrink the file but destroys selectable text and bloats pages with text. IXPDF keeps text as text.
• Ignoring embedded fonts. PDFs that embed full font sets (including unused glyphs) are larger than necessary. Export with subsetted fonts from the source app when you can.
• Expecting a fixed percentage. Reduction depends entirely on how the source was built. A 70% drop on one file and 5% on another is normal.
• Compressing before trimming. If you are going to remove pages anyway, do that first — compressing pages you will throw away is wasted work.