PDF Compressor
Two modes, two honest trade-offs — and a plain statement of how many bytes you actually saved.
Runs in your browser. Nothing you enter here is uploaded to a server.
How to use the pdf compressor
Step 1: Add a PDF
One file, up to 100 MB and 500 pages. Password-protected files are detected and refused.
Step 2: Choose a mode
Optimise structure keeps the pages exactly as they are and removes unnecessary metadata and objects. Rasterise pages converts each page into a compressed image.
Step 3: Set the quality if you rasterise
Resolution and JPEG quality control the trade-off. The warning about what rasterising discards is displayed before you proceed, not after.
Step 4: Compare and decide
The result shows both sizes and the actual change. If the output is larger, the tool says so and recommends keeping the original.
Worked example
A 14 MB scanned contract in both modes
Twelve pages scanned at high resolution, already stored as embedded images.
- Optimise structure
- about 13.7 MB — a 2% saving
- Rasterise at 150 DPI
- about 2.4 MB — an 83% saving
- What rasterising cost
- Any selectable text layer, bookmarks and links
- Page count and size
- Unchanged in both modes
For a scan that was already images, rasterising costs little and saves a great deal. For a text document produced by a word processor, the same operation would destroy the text layer for a much smaller gain.
What each mode does
Structure optimisation rewrites the document without touching page content. Rasterisation renders each page to an image and builds a new PDF from those images.
- Structure optimisation removes document metadata and unused objects and rewrites the cross-reference table. Vectors, text and fonts are all preserved.
- Most of a typical PDF is embedded images and fonts. Structure optimisation cannot touch either, which is why its savings are usually in the low single digits.
- Rasterisation renders at your chosen resolution and re-encodes as JPEG. Everything that was not a visible pixel is gone: text, links, annotations, form fields and tagged structure.
- Page count and physical page dimensions are preserved in both modes, and the result is re-parsed after generation to confirm it is a valid, renderable PDF.
Limitations and privacy
What this tool does not do
- Structure optimisation frequently saves almost nothing. That is an honest outcome, and it will be reported as such rather than dressed up.
- Rasterising destroys selectable text, links, bookmarks, annotations, form fields and accessibility tagging. This is irreversible in the output file.
- Rasterising a text-based PDF often makes the file larger, not smaller, because a page of crisp text compresses far better as text than as an image.
- Image recompression inside an otherwise intact PDF is not available in this version — that is a middle option requiring tooling the browser does not provide.
- Password-protected PDFs are refused. Maximum 100 MB and 500 pages.
The document is parsed, rewritten and re-checked entirely in your browser. No bytes are transmitted, and the original file on your device is never modified.
Frequently asked questions
Why did my PDF barely get smaller?
Because most of its size is embedded images and fonts, and structure optimisation cannot compress those. If the document is a scan, the rasterise mode will help substantially. If it is text, it was probably already efficient.
Will compressing ruin my document?
Structure optimisation will not — pages come through untouched. Rasterising will change the document fundamentally: it becomes a series of pictures, and text, links and form fields are lost. The tool warns you before you choose it.
Which mode should I use?
Start with structure optimisation, since it is safe. If the saving is not enough and the document is a scan or something you only need to view and print, try rasterising and check the result before you discard the original.
Can you compress a PDF without losing quality at all?
Only to the extent that the file contains waste to remove, which is usually not much. Any large reduction involves discarding something — resolution, colour depth, or the text layer. Anyone promising both is not being straight with you.
What if the compressed file is bigger?
The tool tells you plainly and recommends the original. This happens most often when rasterising a text-based PDF, where images of text take more space than the text itself.
Related tools
Other tools people use alongside the pdf compressor.
PDF Merger
Combine up to ten PDFs into one document in any order you like. Pages are copied, not re-rendered, so text stays selectable and page sizes stay exact.
PDF Splitter
Extract pages, split every page into its own file, cut a PDF into ranges or delete pages you do not need. Page sizes and rotation are preserved.
Image Compressor
Compress JPG, PNG and WebP images in your browser. Adjust quality, cap dimensions and download one file or a ZIP. Nothing is uploaded to a server.
PDF to JPG Converter
Render any page of a PDF to a JPG image at your chosen resolution. Pick pages or ranges, preview thumbnails and download single files or a ZIP.
Part of PDF Tools. Last reviewed .