Compress PDF

Reduce PDF file size in your browser.

Runs entirely in your browser. Your data is never uploaded.

About Compress PDF

Compress PDF re-saves your document with optimized object streams to reduce its file size, all locally with pdf-lib. Best results come from PDFs with redundant structure; image-heavy PDFs may compress less.

Compress PDF is one of dozens of free pdf tools on Crystal Toolkit. When you open this page, the tool loads in your browser and is ready to use immediately — there is nothing to install and no account to create. Everything you enter is handled locally using fast, modern web technology, so the work happens on your device rather than on a remote server. This approach keeps your information private, removes upload and download waiting time, and lets the tool keep working even on a slow connection once the page has loaded.

How to use Compress PDF

1Upload a PDF.
2Click compress.
3Download the smaller PDF.

Key features

Edits PDFs locally with the open-source pdf-lib engine
Keeps confidential documents on your device — never uploaded
Handles multi-page documents quickly
100% free with no sign-up, account or watermark
Mobile-first design that works on any device

Common use cases

Combining and organising documents before sharing
Preparing assignments, reports and contracts
Fixing page order and orientation without a desktop app

Why use Crystal Toolkit?

Unlike many online pdf tools, Crystal Toolkit runs Compress PDF entirely inside your browser. That means your data is processed on your own device and is never uploaded to a server, so it stays private and the results appear instantly. There is no sign-up, no daily limit and no watermark — just a fast, focused compress pdf you can use as often as you like, on desktop or mobile. Crystal Toolkit is built and maintained by CrystalSoftonic and is funded by unobtrusive ads, which is how we keep every tool completely free.