Compress PDF
A scanned contract is too big for an email or a form says “max 10 MB”? Drop the PDF here and get a lighter copy in seconds. You’ll see exactly how much it shrank. The file is processed in your browser and is never uploaded anywhere.
Files are processed right in your browser and never uploaded to a server. Open-source libraries
TL;DR. Pick a PDF up to 200 MB and click “Compress PDF”. Recommended mode shrinks images to 150 DPI and keeps text selectable; Strong mode turns pages into images for the smallest file. If the PDF can’t get smaller, you get the original back.
How to compress a PDF
Choose a PDF
Drop the file into the box or click “Choose a file”. One PDF at a time, up to 200 MB.
Pick the level
Recommended suits most files: images get lighter and text stays text. Strong turns each page into an image — the file gets much smaller, but text can no longer be selected.
Compress
Click “Compress PDF”. A progress line shows which stage is running: images, then file structure.
Download
You’ll see the size before and after and the percentage saved. Click “Download” to save the compressed copy. Your original stays untouched.
Your PDF never leaves your device
Most online compressors upload the document to their server, shrink it there and send it back. For bank statements, contracts or medical records that means a copy sits with a stranger for as long as they decide to keep it. Here there is no server step. Compression is done by the open-source libraries qpdf, pdf-lib and pdf.js running inside your browser tab, and the result is saved straight to your device.
You can check it: press F12 (Cmd+Option+I on a Mac), open the Network tab and compress a file. You will only see the tool’s own files loading from our domain — no request carries the contents of your PDF.
How the compression works
Most of a PDF’s weight is usually images: scans, photos, screenshots. A page scanned at 300 DPI is twice as detailed as a screen or an office printer needs, so in Recommended mode every large image is downsampled to 150 DPI and saved as JPEG at quality 70. Images that would get bigger this way are left as they were.
Then the file itself is tidied up: identical images and fonts inserted many times are kept once, internal streams are recompressed with the strongest setting, and metadata, embedded page thumbnails and unused resources are removed. Text, fonts and vector graphics are not touched, so the document stays searchable and prints sharply.
How to compress a PDF for email or to 1 MB
- Email attachments are usually limited to 20–25 MB — Recommended mode is almost always enough for that.
- Government and HR portals often ask for 1–10 MB. Start with Recommended; if the file is still too big, run Strong.
- For a long scan that must fit under 1 MB, split it first with our Split PDF tool and compress the parts.
- A PDF made of text only (exported from Word, for example) is usually already small — compression saves little there.
Why a PDF won’t compress
If the result isn’t at least 1% smaller, you’ll see “already optimized” and get your original back instead of a file that’s just as big. That happens with PDFs that were compressed before or contain only text. A PDF protected with a password or editing restrictions is refused — we don’t remove passwords.
Recommended vs Strong compression
| Recommended | Strong | |
|---|---|---|
| What happens to images | Recompressed to JPEG, downsampled to 150 DPI | The whole page becomes one 110 DPI JPEG |
| Text | Stays text: select, copy, search | Becomes part of the image |
| Links and form fields | Kept | Stop working |
| Typical saving on scans | 40–80% | 70–95% |
| Typical saving on text-only PDFs | Small: such files are already light | Can even grow — then you get the original |
Compress PDF: frequently asked questions
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