Compress PDF
Reduce PDF file size.
How to use Compress PDF
Select the PDF you want to compress.
Pick a compression level: Low keeps the best quality, Recommended balances quality and size, High produces the smallest file.
Click Compress PDF and wait while pages are optimized in your browser.
Compare the original and compressed size, then download the result.
Why your PDF is big in the first place
Almost every oversized PDF is oversized for one of three reasons, and the fix differs for each. Scanned pages are photographs — a colour scan at 600 DPI is roughly 25 MB for ten pages before anything else is added. Embedded photos are often stored at full camera resolution even though the page displays them two inches wide. Embedded fonts add a megabyte or two when the whole font is stored instead of the characters actually used.
A PDF of plain text from a word processor is rarely large. If yours is, something is in it that you cannot see on the page: a hidden layer, an attachment, or an image cropped down to a corner but still stored whole.
Choosing a compression level
Compression trades detail for size, and the right trade depends on where the file is going. Match the level to the destination instead of reaching for maximum by reflex — a file compressed harder than it needed to be cannot be un-compressed later.
- Light — email attachments and archives. Detail preserved; expect 20-40% off.
- Balanced — the everyday default for web uploads and portals. Usually 50-70% off with no visible change at reading zoom.
- Strong — hard limits, and forms that cap you at 2 MB. Text stays readable; photographs visibly soften.
Hitting a specific size limit
Government portals, job applications and university submission systems usually enforce a hard cap: 2 MB, 5 MB, sometimes 500 KB. Start at Balanced and check the result before going further — the largest gain almost always comes from the first pass, and each pass after that costs more quality for less size.
If Strong is still not enough, the file is fighting you somewhere else. Split it and submit in parts if that is allowed, remove pages you do not need, or re-scan in greyscale: a greyscale scan is roughly a third the size of the same page in colour and is perfectly acceptable for most paperwork.
What compression cannot undo
Image compression is lossy, and detail discarded from the compressed copy is gone for good. Keep the original. Nothing here overwrites it — the source file on your device is never modified — but if you delete it after compressing you have no way back.
Every step runs inside your browser, using the WebAssembly and Canvas APIs your device already ships with. No file is uploaded, no copy is kept, and nothing sits in a queue on a server waiting to be deleted — which is also why the tool keeps working with the network disconnected.
Frequently Asked Questions
How does PDF compression work here?
Each page is re-rendered and its images are re-encoded at a lower quality. Recommended and High levels reduce image resolution, which is where most PDF size comes from. Text stays readable, but note that heavily compressed pages are stored as images, so text can no longer be selected in the output.
How much smaller will my PDF be?
It depends on the content. Scanned or image-heavy PDFs often shrink by 60–90%. PDFs that are mostly text are already small and compress less.
Is the compression done on a server?
No. Compression runs entirely in your browser, so your document never leaves your device.
How much smaller will my PDF get?
It depends entirely on what is inside. Scanned or image-heavy documents routinely drop 60-90%. A PDF that is already mostly text may only lose 10-20%, because there was little to reclaim in the first place.
Will the text still be selectable and searchable?
Yes. Text is stored as text, not as pixels, and compression does not touch it. Only images are re-encoded, so search, copy and screen readers keep working exactly as before.
How do I compress a PDF to under 2 MB?
Start with Balanced and look at the result; if it is still over, try Strong. If that is not enough either, the document is probably a high-resolution colour scan — re-scanning it in greyscale at 200-300 DPI achieves more than any compression setting can.
Can I undo the compression?
No. Lossy image compression permanently discards detail in the copy. Your original is untouched, so keep it until you are happy with the result.
Why did my file barely shrink?
Because it was already efficient. A text-only PDF exported from Word or LaTeX has almost no redundancy left. It is also possible it was compressed once already, in which case a second pass costs quality and returns very little.
Does compressing remove passwords or signatures?
Compression rewrites the file's contents, which invalidates any existing digital signature — that is how signatures are designed to work, and it applies to every compression tool. Sign after compressing, never before.
Related tools
Keep reading
- How to Get a PDF Under 2 MB (Without Ruining It)
Why upload forms cap you at 2 MB, why compression alone often fails, and the order of operations that actually gets a scanned document under the limit.
- What Happens to a File You Upload to a Free PDF Site
Free online tools pay for their servers somehow. What the terms usually permit, and why doing the work in the browser removes the question entirely.
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