Compress PDF Online
Use this page when a PDF is too large for email, a school portal, a job application, a client upload, or a document system. The compressor is most useful for scanned and image-heavy PDFs. It is not a guarantee that every file will shrink, and it is not the right method when exact PDF structure must be preserved.
You can use this PDF compressor from a modern browser on Windows, Mac, iPhone, or Android. For larger PDFs, Mac or Windows browsers usually handle memory better than a phone browser.
Choose a PDF to compress
Start with balanced settings. Lower quality or scale only when the file is still too large after the first test.
Drop one PDF here
Your original file is not replaced.
Before you lower the settings
A smaller file is only useful if the receiving person or website can still read it. Start with moderate quality, download the result, and check the smallest details before trying stronger compression.
- Open the downloaded PDF in a normal viewer.
- Zoom to 100% and 150% to check fine text.
- Check page corners, dates, signatures, stamps, and labels.
- Compare the output size with the upload limit.
- Keep the original until the final copy is accepted.
How different PDFs usually behave
| Original file type | Likely result | Best setting approach | Review carefully |
|---|---|---|---|
| Phone scan or scanned paperwork | Often shrinks because pages are image based. | Try medium quality first, then reduce scale if needed. | Small text, signatures, stamps, and ID numbers. |
| Photo-heavy report | May shrink, but image clarity can change. | Keep quality higher if photos are important. | Faces, product labels, receipts, and charts. |
| Text-only PDF | May not shrink much and text may flatten. | Use another optimizer if selectable text is required. | Copy/paste behavior and searchability. |
| Digitally signed PDF | Not recommended. | Keep the original unchanged. | Signature validity and recipient rules. |
Practical file-size strategy
Use default quality and scale. If the result already meets the limit, stop there.
Lower quality slightly when the file is close to the upload limit and images remain readable.
Lower scale only when you need a stronger reduction and the page can tolerate smaller visual detail.
Compression settings explained in plain terms
The quality slider controls how strongly page images are compressed. A lower value can reduce size, but small text and image detail may suffer. The page scale slider controls the rendered page size before rebuilding the output PDF. Lower scale can make the file smaller, but it can also make fine detail harder to read.
For a normal scanned document, use the default settings first. If the output is still too large, reduce quality in small steps. Lower scale only when the file must meet a strict limit and readability remains acceptable.
Common upload-limit situations
Email attachment too large
Try compression if the PDF is image-heavy. If the PDF is text-only, a different optimizer may work better than visual rebuilding.
Application portal rejects file size
Check the exact portal limit before compressing. If the limit is very small, you may need to split the document or ask the receiving party for guidance.
Scanned forms are huge
Scans often contain large images. Compression can help, but you should check every page for blurry writing, seals, stamps, and signatures.
What this compressor does not try to be
This page should not pretend to be a professional prepress optimizer. It does not perform OCR, preserve every interactive PDF feature, repair corrupt files, unlock restricted PDFs, guarantee an exact target size, or certify documents for legal submission. It is a quick browser workflow for everyday file-size problems.
When to stop compressing
Stop once the file meets the upload or email requirement and still looks clear. Extra compression can make text harder to read without providing a useful benefit. If the receiving website accepts a 4 MB PDF, there is usually no reason to force that file down to 500 KB.
For documents that must be read by another person, the best result is not always the smallest file. It is the smallest file that still preserves the information the receiver needs.
More compression guides
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Android and device-specific compression help
Frequently asked questions
Can this compress a scanned PDF?
Yes, it is most useful for scanned or image-heavy PDFs, but you must check whether the output is still readable.
Will text stay selectable?
Not always. This compressor can flatten pages into images, so selectable text and advanced PDF structure may not remain.
Can it guarantee a 1 MB or 500 KB file?
No. The final size depends on the original PDF, number of pages, image detail, and selected quality settings.
Should I use it for signed PDFs?
No. Do not modify digitally signed or official record PDFs unless the receiving party confirms that a changed copy is acceptable.