What PDF compression does here
A PDF's size comes mostly from the images inside it, then from embedded fonts, and only a little from the text itself. Compression tries to store the same pages using fewer bytes. This tool gives you two very different ways of doing that, and choosing the right one matters more than anything else.
| Standard (lossless) | Extra (image-based) | |
|---|---|---|
| What it does | Rewrites the PDF's internal structure more efficiently. Page content is not changed. | Draws each page as a picture (about 94 pixels per inch, JPEG quality around 55%) and builds a new PDF from those pictures. |
| Visual change | None. | Slight softening; very small print can become harder to read. |
| Text | Stays selectable and searchable. | Becomes part of the image — you can no longer select, search or copy it. |
| Links & form fields | Kept. | Removed (they can't exist inside a picture). |
| Typical result | Modest savings; sometimes none on already-optimized files. | Large savings on scans and photo-heavy files; can increase size for text-only documents. |
Either way, the tool shows the original size, the new size and the percentage change, and says plainly if the file could not be made smaller.
When compressing a PDF makes sense
- Email attachment limits. Many email services cap attachments at roughly 20–25 MB, and some workplaces set lower limits.
- Upload forms with a size cap. Government, university and job portals often limit uploads to 2, 5 or 10 MB per file.
- Scanned paperwork. Scans are stored as full-page images and are the files that benefit most — often shrinking substantially in Extra mode.
- Storage and archiving. Smaller files are quicker to back up and to open on phones.
Compression is not useful for a text document exported from Word or Google Docs that is already a few hundred kilobytes: there's little left to remove, and Extra mode would make it both larger and less usable.
How to compress a PDF
- Add one PDF. Drop it on the upload area or click to browse. The tool shows its name, size and page count.
- Try Standard first. It never changes how the document looks, so it's the safe starting point for any file.
- Compress and read the result. If the reduction is enough, download the file (it's saved as
compressed-followed by your file name). - Not enough? Switch to Extra. For scanned or image-heavy PDFs, choose Extra (image-based) and compress again. The tool reads your original each time, so you're never compressing an already-compressed copy.
- Check readability. Open the Extra result and zoom in on the smallest text, signatures and stamps before you send it.
Why some PDFs barely shrink
If Standard mode reports little or no reduction, the file is usually already efficient — for example, a document exported by modern software that has already compressed its images and fonts. There is no hidden setting that can squeeze it further without changing the content.
Extra mode can go the other way. A text-based page is extremely compact: a full page of text might need only a few kilobytes as text, but tens of kilobytes as a picture. That's why the tool warns you when Extra mode made a text-heavy file larger. In that case, keep your original or the Standard result.
The guide to why some PDFs are hard to compress explains this in more depth, including how to spot which kind of PDF you have before you start.
Tips for better results
- Check whether your PDF is scanned. Try selecting a word in your PDF reader. If you can't, the page is an image and Extra mode is likely to help a lot. See scanned vs text-based PDFs.
- Remove pages before compressing. Deleting blank scan pages or appendices you don't need to send with Delete PDF Pages is lossless and often saves as much as compression.
- Keep the original. Extra mode removes selectable text and form fields. Keep the uncompressed file for your own records and send the compressed copy.
- Split instead of squeezing. If a document must stay sharp (engineering drawings, fine print), split it into parts that each fit the limit rather than lowering quality.
- Don't compress a form you still need to fill in. Fill and save it first; Extra mode flattens form fields into the image.
Common compression problems
- "No further reduction possible"
- The file is already efficiently stored (Standard), or it's text-based and grew when turned into images (Extra). You can still download the processed copy, but your original is usually the better file to keep.
- The compressed text looks fuzzy
- Extra mode renders pages at about 94 pixels per inch, which is fine on screen but can soften very small print. If the recipient must read fine print, use Standard mode or split the file instead.
- I can no longer search or copy text
- That is how Extra mode works: every page becomes a picture. Use Standard mode if the text must stay selectable.
- It takes a long time on a large scan
- Extra mode draws every page, which takes a moment per page, especially on phones. Keep the tab open and in the foreground until it finishes.
Compress PDF FAQ
No. Both compression modes run with JavaScript inside your browser, and the compressed file is created on your device. The PDF is not sent to our server as part of compression.
Start with Standard: it never changes how the document looks. Use Extra for scanned documents or PDFs full of photos when Standard doesn't save enough — and check that small text is still readable.
In Extra mode, text-based pages are converted into images, and an image of a page of text is usually larger than the text itself. The tool tells you when this happens. Keep your original, or use Standard mode.
Standard mode keeps text selectable and searchable. Extra mode turns each page into an image, so text can no longer be selected, searched or copied.
It depends entirely on how the PDF was built. Scanned and photo-heavy files often shrink a lot in Extra mode; text documents from word processors may barely change. We show the real result instead of promising a percentage.
Not reliably. The tool doesn't decrypt protected files, so the output may be unusable. If you're authorised to use the file, save an unprotected copy in your usual PDF software first.