Compress PDF
Get a heavy PDF under the upload limit that keeps rejecting it — and see exactly what it costs before you keep the result.
Runs on your device — documents are never uploadedDrop your PDF here
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PDF · scans compress best
120 dpi at 72% JPEG quality.
Every page is re-rendered, so a long document takes real time and real memory. A hundred-page scan is comfortable on a laptop and slow on a phone.
How it works
Three steps, no account, and the document never leaves your computer.
Drop the PDF in
The tool checks whether the document contains real text or is a scan, and tells you what compressing will cost in each case.
Pick a level
Smallest, balanced or best looking. The hint under the buttons says exactly what resolution and quality each one uses.
See the saving, then decide
The before and after sizes appear together. If compressing would not actually help, the tool says so rather than handing you a pointless file.
When a PDF is simply too big
An upload form with a hard limit
Government portals, job applications and insurance claims commonly cap attachments at 2 MB or 5 MB, and a phone-scanned document sails past that.
Email that bounces
Most mail systems reject attachments over about 25 MB, and plenty of corporate ones stop at 10 MB.
A scan at a wildly excessive resolution
Scanner defaults of 600 dpi make sense for archiving artwork and are absurd for a two-page letter.
Sharing a document over a slow connection
A file that takes ten minutes to send on a phone connection is a file that gets sent tomorrow instead.
What actually makes a PDF big
Before compressing anything, it is worth knowing what you are compressing. PDFs get large for a small number of reasons, and only some of them can be fixed.
It is almost always images
Text in a PDF is astonishingly compact. A hundred pages of pure text — a whole novel — is perhaps 1 MB, because the file stores the characters and a reference to a font rather than a picture of the words.
Images are the opposite. One photograph from a modern phone is several megabytes on its own. A page scanned at 600 dpi in colour is roughly 100 megabits of raw pixels before compression. So when a PDF is 40 MB, it is essentially never the text — it is scans, photographs, or a logo embedded at absurd resolution on every page.
This is why the honest first question is: is your document a scan, or is it real text? The tool checks and tells you, because the answer changes everything.
How this compression works, and what it costs
Each page is rendered at a chosen resolution and stored as a JPEG, and those images are assembled into a new PDF. That is a genuine, large saving on image-heavy documents — and it has a real cost that most compression sites do not mention:
- Text stops being text. It becomes pixels. It cannot be selected, copied, searched, or read aloud by a screen reader.
- Sharpness has a ceiling. Zooming in past the chosen resolution shows pixels rather than crisp edges.
- It cannot be undone. The original text is not hiding underneath; it is gone from the new file.
For a scanned document this costs you almost nothing — a scan was already pixels, and it has no selectable text to lose. For a document exported from a word processor it is a real trade, which is why there is a warning rather than a silent conversion.
Choosing a level
| Level | Resolution | Good for |
|---|---|---|
| Smallest | 96 dpi | Reading on screen, getting under a hard limit |
| Balanced | 120 dpi | Most things — clearly smaller, still crisp on screen |
| Best looking | 150 dpi | Anything that will be printed |
For reference: screens are effectively about 96 dpi, ordinary printing wants 150 to 300, and archival scanning uses 600. A document that will only ever be read on a screen gains nothing from 300 dpi except size.
When compression will not help
Some files are already as small as they are going to get, and it is better to be told than to download an identical file with a new name.
A text-only PDF has almost nothing to squeeze — rasterising it can even make it larger, since a picture of a page is bigger than the characters on it. Files already compressed once have had the easy savings taken. And a document that is large because it has eight hundred pages is large for a legitimate reason; splitting it may serve you better than compressing it.
If the result comes out no smaller than the original, this tool says so and suggests keeping what you have.
Better than compressing: not making it huge
If the file came from your own scanner or phone, the real fix is upstream:
- Scan text documents in greyscale or black and white, not colour. Often a five-fold saving on its own.
- Scan at 200–300 dpi. Above that adds size, not legibility.
- Use your scanner's "document" mode rather than "photo" — it is tuned for exactly this.
- If you are photographing pages, crop to the page before making the PDF.
Nothing is uploaded
Rendering, re-encoding and rebuilding all happen in your browser. There is no server, which is why there is no account, no size cap and no watermark stamped onto your document.
It also means the compression is bounded by your own machine rather than by someone's free tier — and that the bank statement you are shrinking to fit an upload form is not sitting in a queue somewhere.
Common questions
Will my text still be selectable afterwards?
No. Compression works by rendering each page and storing it as an image, so text becomes pixels — not selectable, not searchable, not readable by screen readers. For a scanned document that changes nothing, since a scan never had selectable text. For a document made in a word processor it is a real loss, which is why the tool checks and warns you first.
How much smaller will my file get?
It depends entirely on what is in it. Scans and photo-heavy documents commonly drop by 60 to 90 percent. A text document may not shrink at all, and can even grow. The before and after sizes are shown together before you download anything.
Is my document uploaded anywhere?
No. Rendering, re-encoding and rebuilding all happen in your browser using your own processor. Nothing is transmitted, which is why there is no account, no size cap and no watermark.
Which level should I choose?
Balanced unless you have a reason otherwise. Choose Smallest if you are fighting a hard upload limit and the document will only be read on screen. Choose Best looking if it will be printed, since print wants more resolution than a screen does.
Can I undo the compression?
Not from the compressed file — the original detail is genuinely gone. Your original file on disk is untouched though, so keep it until you are happy with the result.
Why did my file not get smaller?
Because there was nothing to squeeze. Text-only PDFs are already tiny for what they contain, and turning them into images can make them bigger. Files compressed once before have had the easy savings taken already. When this happens the tool tells you rather than handing you a pointless download.
What is the best way to avoid huge PDFs?
Fix it at the scanner. Scan text in greyscale rather than colour, at 200 to 300 dpi rather than 600, and use document mode rather than photo mode. Those three settings usually matter more than any compression afterwards.
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Every one of them runs on your device. No uploads, no accounts.