Drop one or more PDFs to shrink their file size — compression runs locally in your browser and files are never uploaded.
Balanced re-renders pages at a good screen resolution and recompresses them — great for most PDFs. Note: image modes make text non-selectable.
Lower = smaller file, more suppression. Higher = better quality. 70–80% is usually visually identical.
Screen reading needs ~96–120 DPI; printing needs ~150–200. Lower DPI = much smaller file.
Advanced (lossless options)
How it works
- How reduction works: the balanced and maximum modes re-render pages and re-encode their images as JPEG at an adjustable quality, which is where most of the size reduction comes from on image-heavy or scanned PDFs. The lossless mode keeps images untouched and only rewrites the file structure, so it reduces size less but never changes image quality.
- Works best on PDFs with lots of repeated objects or bloated internal structure. PDFs already dominated by large photos will see minimal change — sometimes under 5%.
- Metadata removal strips title, author, subject, keywords, and producer fields — a small size win, and a privacy win if you're sharing a document externally.
- For heavy image-based compression, a server-side tool with image re-encoding is genuinely necessary — that's intentionally not what this tool does, and we'd rather say so than overpromise.
- A short ad plays before your download starts — it helps keep this tool free. Processing itself happens instantly; the ad is just a brief pause before the file downloads.
- All processing happens locally in your browser using pdf-lib — your files are never uploaded anywhere.
About compressing a PDF
Compression makes a PDF smaller so it's easier to email or upload. It works mainly by re-encoding the images inside the file at a lower resolution or quality — text usually stays crisp because it's stored as vectors, not pixels.
The whole process runs in your browser; your document is never sent to a server.
Common uses
- Getting a file under an email or upload size limit.
- Shrinking a scan-heavy document that's far larger than it needs to be.
- Reducing a portfolio or report before sharing it widely.
- Saving space when archiving many PDFs.
Use it carefully
Compression trades size for quality. For a text document the loss is usually invisible, but for photos, detailed diagrams or anything you'll print, compress conservatively and check the result at full zoom before relying on it. Always keep the original — compression can't be undone from the smaller file.
Understanding your results
The tool reports the new file size and how much it saved compared with the original. A scan-heavy PDF can shrink dramatically; a text-only one may barely change, because there's little to compress.
Open the compressed file and check the images at 100% zoom. If anything important looks soft, use a gentler setting — the smallest possible file isn't always the right one.
Why did my file barely get smaller?
If it's mostly text, there's little to compress. Big savings come from documents full of images or scans.
Will the text stay sharp?
It depends on the compression mode. Lossless mode keeps the original text and vector structure intact. Balanced and Maximum modes re-render pages as images to achieve stronger compression, which can reduce text sharpness and means the resulting text is no longer selectable as text. Use Lossless when preserving selectable text and the original document structure is important; use the stronger modes when reducing file size is the higher priority.
Is my document uploaded?
No. Compression happens entirely in your browser.
Why PDF file sizes vary so much
A PDF can hold several very different kinds of content: text, vector graphics, embedded fonts, and raster images (photos or scans). Those aren't equal in size. Text and vectors are compact — a description of shapes and characters. Images are heavy, because every pixel has to be stored. That's why two PDFs with the same page count can differ enormously in size.
A useful comparison
A 20-page scanned document can easily be larger than a 100-page text document. Each scanned page is stored as a full image of the paper, while a text page is just the characters and layout. Page count alone tells you very little about file size — the contents decide it.
What this tool can actually reduce
This compressor works in your browser. It reduces size mainly by storing the images inside the file at a lower resolution, and it can optionally remove document metadata. Lowering image resolution is where most of the saving comes from, because images are usually the largest part of a heavy PDF.
Why results differ between documents
A text-only or already-optimised PDF may shrink very little — there simply isn't much image data to compress. A photo-heavy or scanned PDF can shrink a lot. Stronger compression trades some image quality for a smaller file, so it's a balance: compress enough to be convenient, but not so much that the pages look rough.
PDF was created to make documents travel reliably
Adobe introduced PDF in the early 1990s to preserve document appearance across different systems. A major later shift came in 2008 when PDF 1.7 became ISO 32000-1.
Why scanned PDFs become huge
PDF is a container that can hold text, fonts, vectors and images. A scanned page may be stored largely as a high-resolution raster image, so a short scanned PDF can outweigh a much longer text document.