Compress PDF Online: Reduce File Size for Email & Sharing
PDF compressor online: shrink scanned docs and image-heavy PDFs for email. Three quality levels with instant size comparison before you save.
Updated 2026-08-16
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Features
- Compress scanned PDFs: every page is re-encoded as an optimized JPEG, which removes redundant image data for the biggest savings
- Shrink large PDFs for email: reduce multi-megabyte documents down to attachment-friendly sizes under typical 10 MB limits
- Three compression levels: High (quality 0.85), Medium (quality 0.6) and Low (quality 0.35) presets for different needs
- Smart strategy selection: compares page re-encoding against a lossless PDF rewrite and automatically keeps the smaller result
- Text and vector PDFs stay crisp: pure text or vector pages are safely rewritten without rasterization, so text remains selectable
- Preserves page size and count: every page of the original document is kept at the same dimensions and order
- Page-by-page progress: watch exactly where the process is, page by page, even on documents with hundreds of pages
- No page limits: compress documents with hundreds of pages in a single pass
- Instant size comparison: see the original size, the new size and the exact percentage saved before you save the file
- No quotas or file-size caps: large documents are accepted and processed page by page
How to Use
- 1Open the PDF you want to compress by clicking the open area or dragging and dropping the file onto it
- 2Review the original file size and page count that are shown as soon as the document loads
- 3Pick a compression level: High keeps the best quality, Medium balances quality and size, Low produces the smallest file
- 4Click Compress PDF and wait: for large documents, progress is shown page by page
- 5Compare the original and compressed sizes along with the exact percentage saved
- 6Click Save PDF to store the compressed file on your device, keeping the original untouched
- 7For scanned or image-heavy PDFs, choose Medium or Low: re-encoding removes redundant image data for the largest savings
- 8For text-only PDFs, any level works: the tool detects that re-encoding would not help and applies a safe rewrite instead
- 9Compressing a PDF for email? Use Low and aim for under 10 MB so the file fits common attachment limits
- 10Need to keep print quality? Use High: pages keep their resolution while the file still becomes noticeably smaller
Frequently Asked Questions
How much can I compress a PDF?
Savings depend on the content. Scanned and image-heavy PDFs typically shrink by 50-80%, while text-heavy PDFs often shrink by 10-40%. The tool always compares both compression strategies and keeps the smaller output, so you get the best possible result for your file.
Is there a difference between compressing text PDFs and scanned PDFs?
Yes. Scanned PDFs are built from large images, so re-encoding every page as an optimized JPEG removes most of the weight: this is why they typically shrink by 50-80%. Text and vector PDFs contain fonts and paths that do not rasterize well, so the tool applies a lossless rewrite that strips redundant objects instead: the text stays crisp and searchable, with typical savings of 10-40%.
What do the High, Medium and Low levels mean?
They map to JPEG quality values of 0.85, 0.6 and 0.35 used when re-encoding pages. High looks nearly identical to the original, Medium is a balanced default for most documents, and Low produces the smallest file: ideal for email attachments or long-term archiving where slight softening is acceptable.
Will my text remain readable and searchable?
For scanned documents the text is part of the image: it stays fully readable, but it is not a text layer, so search and copy will not find it, exactly as in the original scan. For text-based PDFs, the tool's rewrite strategy preserves the original text layer, so words remain selectable and searchable. Page re-encoding is only kept when it produces a smaller file than the rewrite.
Why didn't my PDF get smaller?
Some files are already well optimized: PDFs created from compressed images, small text-only documents, or files previously compressed with another tool often cannot shrink further. In that case the tool shows a notice and lets you save the cleaned-up rewrite anyway.
Can I compress a scanned PDF?
Yes, and it is where the tool shines. Scanned pages are stored as large uncompressed or lightly compressed images, so rendering each page and re-encoding it as a tuned JPEG routinely cuts file size by 50% or more while keeping text fully legible.
Can I compress a PDF to an exact size like 500 KB or 1 MB?
There is no exact target-size mode: the tool compresses with three fixed quality presets. Low (quality 0.35) is the smallest setting and typically brings scanned PDFs under 10 MB; a further pass with Low can often reach 1 MB for image-heavy documents, but a 200 KB or 500 KB target is only realistic for short, mostly-image PDFs. If an exact size is mandatory, use a desktop tool like Ghostscript with explicit downsampling settings.
Why does my compressed PDF look blurry?
Blur usually comes from the Low preset: pages are re-encoded as JPEG at quality 0.35, which visibly softens text edges and gradients when zoomed or printed. If sharpness matters, choose High (0.85): files stay noticeably smaller while text stays crisp. A blurry output can also simply reflect a low-resolution source scan, which no compression level can recover.
Can I compress multiple PDFs at once?
No, this tool processes one PDF at a time, page by page, with live progress. For batch work, compress each file here in sequence, or use a command-line tool like Ghostscript once you know the settings that suit your documents.
Which compression level should I choose?
Use High for documents that will be printed or read carefully on screen, Medium for everyday sharing where quality still matters, and Low for emails, uploads or archives where size is the priority. When in doubt, start with Medium (JPEG quality 0.6) and check the preview sizes.
Is there a limit on file size or number of pages?
There is no artificial limit. The only constraint is your device's memory: very large PDFs with hundreds of pages are processed page by page, so memory usage stays bounded and progress is shown throughout.
Why can't I compress a password-protected PDF?
Encrypted PDFs are locked with AES-128 or AES-256 encryption, and the browser cannot decode them without the owner password: this tool never asks for or stores passwords. Unlock the file with a PDF decryption tool first (the error screen points to one), then compress the unencrypted copy. This limit comes from the PDF encryption format itself.
Will the page size and layout stay the same?
Yes. Every page keeps its original dimensions and order, and each page is rendered at the same aspect ratio. The compression affects image encoding only, so nothing is cropped, rotated or reflowed.
What happens to bookmarks, links and metadata?
The re-encoded output is rebuilt from the rendered pages, so interactive features such as links and bookmarks are not carried over. When the rewrite strategy wins, the document structure and metadata are preserved. For heavily interactive PDFs, consider using High so the rewrite is more likely to be selected.
How do I compress a PDF for email?
Select the file, choose the Low level, click Compress PDF and save the result. The percentage indicator tells you when the file drops below common attachment limits such as 10 MB, and the tool shows the final size before you save.
Does the tool work on mobile?
Yes. The interface is fully responsive and works in mobile browsers: open the PDF from your files app, compress it, and save the result to your device. Because everything runs locally, no network connection is needed during processing.