Compress PDF Online
Choose between a gentle clean-up that keeps selectable text and three stronger modes that turn pages into compressed images. The result shows exactly how much was saved.
A PDF can be large for very different reasons. A scanned document is a stack of page photographs, so its size comes from images. A report exported from a word processor is mostly text and a few charts, so it is often small already. A brochure with full-bleed photographs falls somewhere in between. Because the cause differs, no single "compress" button works for every file, and this tool gives you a choice of strategies instead of pretending otherwise.
The four compression modes
The Compression mode menu offers one gentle option and three that rebuild the file from page images. Here is what each really does, based on how the tool is built.
| Mode | Method | Text stays selectable? | Typical use |
|---|---|---|---|
| Keep text & links (small savings) | Re-saves the file with a more compact internal structure. Pages are not redrawn. | Yes, links too | Text-based PDFs where you cannot afford to lose searchability |
| Smallest (low quality) | Draws each page at 1x scale and stores it as a JPEG at 50% quality. | No | Scans that must fit under a tight email limit |
| Balanced (medium) | Draws each page at 1.5x scale, JPEG at 65% quality. | No | General sharing of scans and photo-heavy files |
| Higher quality | Draws each page at 2x scale, JPEG at 80% quality. | No | Files you still want to print legibly |
Know the trade-off: the three image-based modes flatten every page into a picture. Text can no longer be selected, searched or copied, and links stop working. Hyperlinks, form fields and bookmarks are not carried over. Keep your original file if you might need those things later.
How to compress a PDF
- Click Select PDF and choose your file.
- Pick a mode from Compression mode. If you are unsure, start with the default, then try Balanced.
- Click Compress. For the image modes the result area counts pages as they are processed, which can take a while on long documents.
- When the work finishes, the tool shows the original size, the new size and the percentage saved, and the file downloads as
compressed.pdf.
When nothing is downloaded
The tool only gives you a file if it is genuinely smaller than your original. If a mode produces a larger or equal file, you will see a message with the original size and the size it reached, and no download starts. This is a feature: it stops you from replacing a good file with a worse one. Two situations commonly trigger it. A text-based PDF that is already compact has little to squeeze, so the light mode cannot improve it. And a PDF that is mostly vector graphics and text may grow when converted to images, because a photograph of a page can be heavier than the instructions that draw it.
Choosing a mode in practice
A scanned contract of 20 pages
Scans are already images, so the image modes work well. Try Balanced first. Zoom in to check that signatures and small print are still readable. If it is too soft, switch to Higher quality; if you need more savings, try Smallest.
A report exported from a word processor
Start with the default, which keeps text. If the savings are minor, remember that the real fix is usually upstream: re-export from the original program with a lower image resolution setting, or replace oversized photographs before exporting.
A photo brochure
Balanced is usually a sensible compromise. Photographs tolerate JPEG compression better than line art, so check any logos or thin lines at full zoom afterwards.
Understanding the numbers
The scale setting controls resolution. At 1x, a standard A4 page is roughly 595 by 842 pixels, which looks fine on a phone but coarse when printed. At 2x it is about 1190 by 1684 pixels, which is closer to comfortable reading and light printing. JPEG quality trades file size for fidelity: 50% shows visible blockiness around text edges, while 80% is hard to distinguish from the original at normal viewing size. Page dimensions are kept the same as your original, so the document still prints at its intended paper size.
Privacy and processing
Compression happens in your browser. Your file is read from your device and processed locally; it is not uploaded for compression. To do the work, the page loads two open-source libraries (a PDF reader and a PDF writer) from a public content-delivery network the first time you use it, so you need an internet connection for the initial load.
Tips for better results
- Large, very long PDFs use a lot of browser memory in the image modes. If the page becomes slow, split the file first with the Split PDF tool, compress the pieces, then merge them again.
- Compare the result in a viewer before deleting the original, particularly if the document contains signatures, stamps or fine drawings.
- Do not compress files you plan to run text recognition or search on later, unless you keep the uncompressed original as well.
- If you need to reduce size and keep selectable text, lowering the image quality at the source is the only reliable method.
Frequently asked questions
Why did the tool say it could not make my file smaller?
The result was the same size or larger, so it was discarded. Try a different mode, or accept that the file is already compact.
Will compressed PDFs lose their hyperlinks?
In the three image-based modes, yes: every page becomes a picture. In the default mode, links and text are kept.
Is there a way to set an exact target size?
No. The tool offers fixed presets. Try them from Smallest upward until you find one that meets your limit with acceptable clarity.
Does it work on password-protected PDFs?
Not reliably. The tool is not designed to unlock files, so remove the password in the program that created it first.
Is the original file changed?
No. Your file stays as it is on your device; the tool creates a separate compressed copy.