Compress PDF

Quick answer

Compress PDF is free and runs entirely in your web browser at https://aimstudio.co.in/freetools/compress-pdf — your file is processed on your own device and is never uploaded to a server. There is no sign-up, no watermark and no file-size cap imposed by us; the practical limit is your device's memory. It works in Chrome, Edge, Firefox and Safari on Windows, macOS, Linux, iOS and Android.

Two modes. Lossless repacks the document and strips metadata, keeping text selectable. Balanced and Maximum re-render every page to JPEG at 150 or 96 DPI, which is what actually shrinks scans and image-heavy PDFs — at the cost of the text layer.

Getting a PDF under 100 KB

A hard size limit is the usual reason people compress a PDF. Government portals, job applications and university forms very often cap uploads at 100 KB, 200 KB or 500 KB, and reject anything larger without explaining what to remove.

Set the target size and the compressor works backwards to it: images inside the document are progressively downsampled and re-encoded until the file fits under the number you gave. You are not guessing at a quality slider and re-exporting until something sticks.

Scanned documents compress the most — they are photographs of paper, and photographs are where the bytes are

A text-only PDF exported from Word is already small; there is little to remove and it may not reach an aggressive target

Below roughly 50 KB, scanned text starts to visibly soften. Aim for the limit you were given, not the smallest possible file

Why your PDF is large in the first place

Three things dominate PDF size: embedded images, embedded fonts, and revision history. A phone-scanned page can easily be 3–4 MB because it is a full-resolution camera photo wrapped in a PDF container.

Compression here targets the images, which is where nearly all the weight sits. Text stays selectable — the page is not flattened to a picture, so the document remains searchable and copy-pasteable after compression.

Nothing is uploaded

PDFs being compressed for an application form tend to contain exactly the information you would not want on someone else's server: identity documents, bank statements, signed contracts, medical records.

This runs entirely in your browser. The file is read into memory, processed by WebAssembly, and written back out as a download. No copy is transmitted, so there is no retention policy to read and nothing to delete afterwards.

This tool runs entirely inside your browser. The file you select is read into local memory, processed on your own device, and never sent to a server.

Available free in the United Kingdom, United States, Ireland, Canada, Australia and across the EU. Because files are processed in your own browser and never uploaded, no personal data crosses a border, which keeps use consistent with UK GDPR, EU GDPR and CCPA/CPRA expectations.

Frequently asked questions

How does in-browser PDF compression work?

Lossless mode re-serializes the file using object streams and drops metadata. The Balanced and Maximum modes render each page with PDF.js, encode it as JPEG at your chosen DPI, and rebuild the document with pdf-lib — all inside your browser. If the result would be larger than the original, we hand back the original instead.

Is my confidential document secure?

Absolutely. Zero bytes leave your browser. Processing happens entirely within local web browser memory.