Got a PDF that's too large to email, too slow to share, or just taking up more space than it should? Compressing it takes seconds — and you don't need to hand your file over to anyone to do it.
PDF file size is usually down to one of a few things:
For most everyday PDFs — reports, invoices, presentations — a good compressor can cut the file size significantly without any visible quality loss.
Most online tools work the same way: you upload your file to their server, it gets processed, and a download link comes back. Fast and easy — but your file has just been sent to a third party.
For a random PDF that's fine. But for contracts, financial documents, HR files, or anything with personal information, that's a risk most people don't think about until it's too late.
DocKiit runs entirely in your browser. When you compress a PDF, the file is processed locally using JavaScript — it never gets sent to a server, never touches our infrastructure, and never leaves your device. What you're doing is closer to your browser doing the work than uploading a file anywhere.
It's not a policy or a promise — it's just how the technology works. There's no server to breach because there's no server involved.
Head to DocKiit and select Compress PDF from the homepage. This is a Pro feature — you'll need a DocKiit Pro account to access it.
Click Choose File or drag and drop your PDF onto the page. The file loads instantly in your browser — no waiting for an upload to complete.
Hit Compress and your optimised PDF downloads straight to your device. DocKiit shows you the before and after file size once compressed, so you can see exactly how much smaller it got.
DocKiit Pro gives you access to PDF compression, merging, watermarking and more — all processed locally in your browser. USD $9.99/mo.
Start Pro →Mac users can compress PDFs through the built-in Preview app. Open your PDF, go to File → Export as PDF, and use the Quartz Filter dropdown to select Reduce File Size. It works, but the quality reduction can be aggressive — fine for internal docs, not ideal for anything client-facing.
Windows doesn't have a native PDF compressor. Your best options are a browser-based tool like DocKiit, or Adobe Acrobat if you have a subscription. For most people, a free online tool is the fastest route — just be mindful of what you're uploading and where.
Open your mobile browser, go to DocKiit, and follow the same steps. No app download needed — it works on any device with a modern browser.
For text-heavy PDFs — reports, invoices, contracts — compression has no visible impact on quality. For PDFs with lots of high-resolution images, there may be a slight reduction, though for most use cases it won't be noticeable.
It depends on the file. Text-heavy PDFs with unoptimised structure can shrink significantly. Image-heavy or already-optimised PDFs will see smaller gains. DocKiit shows you the exact before and after size so you always know what you're getting.
With DocKiit, yes — your file never leaves your browser, so there's nothing to intercept. With other tools, you're trusting a third party with your file. For sensitive documents, that's worth thinking about.
You'll need to remove the password protection before compressing. Most PDF tools, including DocKiit, require the file to be unlocked before processing.
DocKiit handles most standard PDF sizes. For very large files, browser-based processing may be slower than server-side tools — but the privacy tradeoff is worth it for sensitive documents.
Yes — smaller files open faster, especially on slower connections or mobile devices. It also makes them quicker to email, upload to cloud storage, or share via messaging apps.