Guide
How to compress a PDF
Most PDFs get rejected by email and government upload forms for one reason: the file is too big. Compressing rewrites the file so it carries less overhead. It takes a few seconds and, here, it happens on your own device — the PDF is never sent anywhere.
Steps
Open the Compress tool
Go to Compress PDF and click to choose your file. Nothing is uploaded when you pick it — the browser reads it straight from your device.
Check the size it reports
The tool shows the file size as soon as you choose it. Note that number: it is what you are trying to get under, and it is how you will know whether compressing was worth it.
Press Compress PDF
You get the result as a percentage plus a before-and-after size, so you can see immediately whether it helped. If the file was already efficiently saved, the tool says so and does not hand you a "compressed" copy that is bigger than what you started with.
Download and check it opens
Open the downloaded file before you send it. Compression here does not touch your text or images, so it should look identical — if anything looks wrong, use the original.
If your PDF is a scan, compression here will not do much. That is a limit of rewriting structure rather than re-encoding images, and it is better to say so than to have you try three times and wonder what you did wrong.
Common questions
Why did my file barely get smaller?
Because of what is inside it. This tool strips redundant structure from the PDF — it does not recompress photos. A text-heavy document shrinks noticeably. A scanned document is essentially a stack of images, so there is little structure to remove and the size barely moves.
Will compressing lower the quality?
No. Nothing is re-encoded and no image is downsampled. The words and pictures come out byte-for-byte the same; only the file plumbing changes.
Is my file uploaded to a server?
No. The compression runs in your browser tab. You can confirm it yourself: open your browser network tab, compress a file, and watch that nothing leaves.
What if it is still too large?
Split it. If the form only needs certain pages, use Split PDF to pull out just those — a five-page extract from a fifty-page document is dramatically smaller than any compression can achieve.