How to compress a PDF and reduce its size
Compressing a PDF reduces its file size so it is easier to email, upload or store, while keeping the document readable. Large PDFs are usually heavy because of high-resolution scans and embedded images; compression re-encodes those images and removes redundant data so the file shrinks, often dramatically, without changing the words on the page.
Our tool offers several compression levels so you can balance size against visual quality for your particular document.
How much a file shrinks depends almost entirely on what is inside it. A 40 MB folder of 300 DPI colour scans routinely comes back under 8 MB, while a text-only contract exported from Word might lose only a few percent — it was never bloated to begin with. The before-and-after sizes shown after processing tell you immediately whether the result fits your limit.
Step by step
- Open the Compress PDF tool and upload the file you want to shrink.
- Choose a compression level — lighter compression preserves more detail, stronger compression produces a smaller file.
- Press Process and let the tool optimise the document.
- Compare the new size with the original shown on screen.
- Download your smaller PDF, ready to send or archive.
Limits and formats at a glance
| Input | Any standard PDF up to 20 MB free (1 GB with PRO) |
|---|---|
| Compression levels | Light, recommended and strong — you choose the trade-off |
| Typical reduction | 60–90 % on scans and image-heavy files; less on pure text |
| Text quality | Never touched — text is not an image and stays vector-sharp |
| Output | A standard PDF that opens in any reader |
| Cost | Free, no account required |
Why use this tool
Most email providers reject attachments above 20 to 25 MB, and slow connections make large uploads painful. A compressed PDF clears these hurdles and reaches the recipient faster, which matters when you are sending a proposal against a deadline or uploading a form to a portal with a strict size cap.
Smaller files also save storage across your devices and backups. Over hundreds of documents, the space recovered by compression adds up significantly.
Compression works by rebuilding the parts of a PDF that take up the most room. Photographs and scanned pages are re-encoded as efficient JPEGs at a sensible resolution, duplicated resources such as repeated fonts or logos are stored once instead of many times, and invisible metadata and unused objects are stripped out. The text layer itself is left untouched, which is why a scanned brochure can lose 80 % of its weight while a text-only report barely changes.
Compression also has a natural place in longer workflows: merge several scans first and compress the combined file once, rather than compressing each piece; compress before uploading to portals with strict caps such as job applications, court filings or university submissions; and if a document must also be archived, keep the uncompressed original and circulate the compressed copy. For files that need to meet a formal archiving standard, use PDF to PDF/A instead — archival requirements and maximum compression pull in opposite directions.
Is it safe? Your privacy
The document you upload is used only to create the compressed copy and is erased from our servers automatically within minutes. Its contents are never inspected or kept.
Troubleshooting: common problems and fixes
- The file barely shrank. — It is probably mostly text, which is already efficient. Real savings come from images and scans; a 200 KB text-only report has little left to remove.
- Photos look too soft after compression. — Re-compress from the original with a lighter level. Always keep the source file so you can retry with different settings instead of compressing an already-compressed copy.
- I must get under a hard limit and the file is still over it. — Try the strongest level first. If that is not enough, divide the document with Split PDF and send it in parts — two 8 MB halves pass where one 16 MB file is refused.
- The PDF will not upload because it is password-protected. — Encrypted files cannot be rebuilt. Remove the password with Unlock PDF, compress, then protect the result again.
Frequently asked questions
Will compression make my text blurry?
Text stays crisp because it is not an image. Only embedded pictures are re-encoded, and the lighter levels keep them looking clean.
Why is my PDF so large to begin with?
Usually because it contains full-resolution scans or photos. These compress the most, which is why scanned documents often shrink the furthest.
Which compression level should I choose?
Start with the recommended level: it gives a clear size reduction while keeping images visually clean, which is right for most emails and uploads. Use the stronger level when you must hit a tight size limit and can accept slightly softer photos; keep the lighter level for documents you will print.
How small will my file actually get?
It depends entirely on the content. Image-heavy or scanned PDFs often drop by 60–90 %, whereas a file that is mostly text may only shrink a little because there is little redundant data to remove.
Does compressing the same PDF twice help?
Rarely. After the first pass the images are already optimised, so a second compression saves almost nothing and can needlessly reduce quality. Compress once from the original whenever possible.
Is it safe for confidential documents?
Yes. The file is processed only to produce the smaller copy and is deleted automatically within minutes; we never open, store or share its contents.
Does compression remove pages or content?
Never. Every page, word and image stays in the document; only the way images and internal data are encoded changes. If you need to drop pages too, use Split PDF first.
Will forms, links and bookmarks still work?
Yes. Compression rebuilds images and internal streams, not the interactive layer, so fillable fields, hyperlinks and bookmarks survive intact.