How PDF compression works
The tool starts by analyzing the PDF structure: text pages, image pages, and mixed pages. Text pages are rebuilt as PDF without rasterizing, so text remains selectable. Image pages are reduced by DPI and quality, and the forecast estimates the final protected size before compression starts.
How to use
- Add one or more PDF files and wait for structure analysis.
- If the file contains image pages, adjust resolution and quality while watching the forecast.
- Press Compress, then download the result or change the settings and run another version.
How PDF size is reduced
The tool first analyzes the document structure: text pages, scanned pages, images, and mixed pages. Text PDFs are not converted into pictures, so text remains selectable and searchable.
Most savings usually come from image pages: they are rebuilt with the selected DPI and quality. The forecast helps you decide whether compression is worth running or whether the original is already good enough.
DPI, quality, and scans
DPI controls the size of raster pages. A moderate value is often enough for screen reading, while print documents should not be reduced too aggressively. The quality slider affects JPEG/WebP and reduces the color palette for PNG.
Scanned documents can become much smaller, but small text and stamps are sensitive to excessive DPI reduction. If the PDF contains important signatures, diagrams, or small tables, compare the result with the original before sending it.
When compression cannot help
Some PDFs are already optimized or consist mostly of text and vector graphics. In that case the rebuilt file may not be smaller, and the tool keeps the original version.
Processing runs locally in the browser, so very large files, damaged documents, or password-protected PDFs depend on device memory and browser capabilities.