Compress PDF
Shrink a PDF by recompressing its embedded images. Runs entirely in your browser — files are never uploaded to a server.
Click to upload or drag and drop
Select a PDF file
How it works
Most large PDFs are large because of embedded images, not text. This tool finds each JPEG image inside the PDF, redraws it at a lower quality and (for higher compression levels) a smaller resolution, and puts the smaller version back — the surrounding text and vector content is never touched, so it stays sharp and selectable. Images in other embedded formats are safely left as-is rather than risking a broken result. If a PDF has no recompressible images, only a genuinely lossless internal restructuring is applied.
Is this lossless?
Only when no images were recompressed. Whenever images are recompressed, this is a lossy reduction — the result summary tells you exactly which case applied to your file.
The three compression levels
- Recommended: JPEG quality 75%, and any image whose longer side is over 2000 pixels is scaled down to 2000.
- Strong compression: quality 55%, longer side capped at 1400 pixels.
- Maximum compression: quality 35%, longer side capped at 1000 pixels.
- Images are only made smaller, never enlarged, and the proportions are kept. A 4000 × 3000 photo becomes 2000 × 1500 at Recommended, 1400 × 1050 at Strong and 1000 × 750 at Maximum. A 1600 × 1200 image is scaled to 1400 × 1050 at Strong and 1000 × 750 at Maximum, but keeps its size at Recommended.
What gets recompressed and what is left alone
Only JPEG images (the DCTDecode kind) that are referenced directly on a page are processed. Each recompressed version is kept only if it is smaller than the original data; otherwise the original stays and counts as left unchanged. Images in other formats are also left as they are, and so are CMYK images and images with a custom decode array, which are never re-encoded, and text and vector drawings are never touched.
Reading the result summary
The result screen shows the sizes before and after in the form 12.40 MB → 3.10 MB, with the percentage saved rounded to a whole number. If the saving rounds to zero or less it says "no significant reduction". A line underneath states how many images were recompressed and how many were left unchanged. The download is named compressed.pdf, and PDFs up to 100 MB are accepted.
Guides
- How to Compress a PDF Without Losing Quality — What actually makes a PDF large, and how to shrink it while keeping text and images looking right.
- How to Get a PDF Under 200 KB, 1 MB or 2 MB — A step-by-step order for getting a PDF under a portal's size limit, what sets the minimum size, and what to do when compression alone isn't enough.
Frequently asked questions
Is this lossless compression?
Only when your PDF has no recompressible images — in that case, a genuinely lossless internal restructuring is applied. Whenever images are recompressed, the result is a lossy reduction, which the tool tells you clearly.
Why didn't my PDF get much smaller?
If your PDF is mostly text with few or no embedded JPEG images, there's little this tool can safely shrink — text and vector content are never touched, and only certain image formats can be safely recompressed.
What does "images left unchanged" mean?
Those images were either stored in a format the tool does not recompress or, when re-encoded as a JPEG, did not come out smaller than the original, so the original was kept.
Guide: How to Compress a PDF Without Losing Quality