Shrink large PDFs for email, upload or storage. Each page is re-rendered, so you choose how much resolution to trade for size — and your page dimensions stay as they were. No signup.
Compress PDF NowReduce your PDF file size in three easy steps
Drag and drop your PDF file or click to browse. We show the current file size immediately.
Pick Less compression (~144 DPI), Recommended (~101 DPI) or Extreme (~65 DPI). Add grayscale if the document is black and white anyway.
Click compress and download your smaller PDF. See exactly how much space you saved.
Compression here works by re-rendering each page as a JPEG. Knowing the numbers tells you which level to pick.
| Level | Renders at | JPEG quality | Use it when |
|---|---|---|---|
| Less compression | ~144 DPI | 85% | The document matters and you only need a moderate saving |
| Recommended | ~101 DPI | 70% | Scans and photo-heavy files headed for email |
| Extreme | ~65 DPI | 50% | A hard size ceiling, and the document is a reference copy |
There is also a Convert to grayscale switch, which drops the colour channels. On a black-and-white text scan that is close to a free saving; on anything with colour photographs or coloured highlighting it is a visible change, so check the result.
The page size is preserved at every level. An A4 page comes out A4, whichever setting you choose.
What changes is the resolution the page is drawn at. For reference, 300 DPI is what a good scanner produces and what a commercial printer wants; 144 DPI is comfortable on screen and fine on an office printer; 65 DPI is a screen-reading copy and will look soft in print. If you know the file needs to be printed properly later, keep the original.
Every page becomes an image. That has consequences worth knowing before you replace your only copy.
This is the honest core of it, and an earlier version of this page got it wrong. Compression does not pick through your document optimising images while leaving text alone. It re-renders each page into a picture and rebuilds the file from those pictures. So:
Keep the original. Compression is a one-way door — there is no way to get the text layer back from an image. Treat the compressed file as a copy made for a particular purpose, such as an email attachment, rather than as a replacement for the document.
If you need a smaller file and selectable text, this is the wrong tool. Two better routes: remove the pages you do not need, which is lossless, or go back to whatever produced the PDF and export it again with its images at a lower resolution. Word, Pages and InDesign all let you choose that at export time, and the result keeps real text throughout.
It sounds like a contradiction. It is the most common complaint about every browser-based compressor, including this one.
A PDF full of text is extremely efficient already. The file stores the characters, a reference to a font, and coordinates — a few kilobytes for a page of prose. Turn that page into a JPEG and you are now storing a few hundred thousand pixels instead. The picture is almost always heavier than the text it replaced.
We measured it while writing this page: a single-page text document that was under 1 KB came out at 16.9 KB at Less compression, 9.1 KB at Recommended, and 4.8 KB even at Extreme. Every setting made it larger. Real documents are bigger than that test file, but the direction of travel is the same.
When the weight is already in images. Compression works on the thing that is actually large, so the wins come from:
A quick way to tell which kind of file you have: open it and try to select a sentence with your cursor. If the text highlights, it is a text document and compression will probably not help. If nothing highlights, it is a scan, and it probably will.
The reason most people arrive here, and the numbers that actually apply.
Gmail's ceiling is 25 MB, and Outlook.com's is 20 MB. The trap is that attachments are encoded before sending, which inflates them by roughly a third — so a 20 MB PDF can arrive at the limit as about 27 MB and bounce. Aim for a comfortable margin rather than the stated figure: under about 18 MB for Gmail, under about 14 MB for Outlook.
A sensible order to try things in:
For a legal filing, a printed submission or anything going to a commercial printer, do not compress at all. Those all have their own resolution requirements, and a file that has been through a 65 DPI round trip cannot meet them.
More tools to optimize your PDF documents
Including what compression will cost you, which is the part you need before you start.
You cannot, strictly - compression here re-renders each page as a JPEG, so there is always a trade. The useful question is how much you are giving up. Less compression renders at about 144 DPI at 85% JPEG quality, which looks sharp on screen and prints acceptably; Recommended is about 101 DPI at 70%; Extreme is about 65 DPI at 50%. For a scan, Recommended usually cuts the file a long way with no difference you would notice on screen. If you genuinely cannot lose anything, remove unneeded pages instead, which is lossless.
At the stronger levels, yes. Because every page is re-rendered as an image, text becomes pixels and its sharpness depends on the level you picked. At Less compression, around 144 DPI, text stays comfortable on screen and on an office printer. At Extreme, around 65 DPI, small type visibly softens. Separately, and at every level, the text stops being selectable or searchable.
No. This is the most important thing to know before you compress anything. Each page is flattened into an image, so clickable links, interactive annotations and fillable form fields do not survive - a compressed form becomes a flat picture of a form that nobody can fill in. If your document has fields or links that matter, do not compress it.
Because your document was mostly text. A page of text is stored very efficiently as characters and font references, often a few kilobytes; converting it to a JPEG replaces that with a few hundred thousand pixels, which is heavier. Compression only helps when the file's weight is already in images. A quick test: try to select a sentence in your PDF. If the text highlights, compression will probably not help it.
It depends entirely on what is inside it, so we do not publish a percentage - any figure quoted without knowing your document is guesswork. A 300 DPI scan compressed at Recommended typically drops a great deal, because it is being re-rendered at a third of its resolution. A text report may not shrink at all, or may grow. Run it and look at the result.
No. The pages keep their original dimensions at every level - an A4 page stays A4. Only the resolution the page is drawn at changes. If you want to change the physical page size, that is a different job and the resize tool does it.
It removes the colour channels before the page is encoded. On a black-and-white text scan that is nearly a free saving, because the colour information was carrying nothing. On anything with photographs or coloured highlighting it is an obvious visual change, so look at the output before you rely on it.
Free for files up to 50MB, with no watermark and no signup; Pro accounts handle files up to 300MB. Nothing is uploaded - your browser opens, re-renders and rewrites the PDF locally, so the file never leaves your device.
No. Both have resolution requirements that a compressed file cannot meet, and a page that has been re-rendered at 65 or even 144 DPI cannot be restored to print quality afterwards. Send the original, and if it is too large to send, share it from cloud storage instead.
No. Once a page has been turned into an image there is no way to recover the text layer or the vector artwork, so keep your original file. Treat the compressed version as a copy made for a specific purpose rather than a replacement.
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