Will photos lose quality?
No. This mode recompresses PDF structures without deliberately downsampling or recompressing image pixels.
- Lossless stream recompression
Guide
Reduce avoidable PDF structure overhead without sending the file to a compression service.
Apply lossless PDF stream recompression and object packing locally, with an optional fast-web-view pass and exact before-and-after sizes.
Clear answers
Reduce avoidable PDF structure overhead without sending the file to a compression service.
Apply lossless PDF stream recompression and object packing locally, with an optional fast-web-view pass and exact before-and-after sizes.
Why is the reduction small?
Photographs and many generated PDFs are already compressed. Structural optimization cannot always reduce them further.
- Object-stream packing
Is the file uploaded?
No. Compression runs through a WebAssembly PDF engine in this browser.
- Exact size comparison
A local check
Reduce avoidable PDF structure overhead without sending the file to a compression service.
Apply lossless PDF stream recompression and object packing locally, with an optional fast-web-view pass and exact before-and-after sizes.
Selected file
Choose an unencrypted PDF.
Choose an unencrypted PDF.
Review before sharing
Object-stream packing
Select the compression level and optional fast-web-view layout.
Local verification
Create the compressed copy locally.
Create the compressed copy locally.
Compare sizes and reopen the result before replacing any file.
Four local steps
Why is the reduction small?
- 01
Lossless stream recompression
Choose an unencrypted PDF.
- 02
Object-stream packing
Select the compression level and optional fast-web-view layout.
- 03
Exact size comparison
Create the compressed copy locally.
- 04
Lossless stream recompression
Compare sizes and reopen the result before replacing any file.
Browser privacy
Compress a PDF Locally
Lossless stream recompression
No. This mode recompresses PDF structures without deliberately downsampling or recompressing image pixels.
Object-stream packing
Photographs and many generated PDFs are already compressed. Structural optimization cannot always reduce them further.
Exact size comparison
No. Compression runs through a WebAssembly PDF engine in this browser.
Clear answers
Is the file uploaded?
No. Compression runs through a WebAssembly PDF engine in this browser.
- Already optimized PDFs may become only slightly smaller or occasionally larger.
- Lossless mode does not downsample photographs.
- Rebuilding can invalidate signatures.
Private workspace
Compress a PDF Locally
Reduce avoidable PDF structure overhead without sending the file to a compression service.