# Compress PDF > Browser-only file conversion. Selected files are processed on this device and are not uploaded to a conversion server. Source: https://localconverter.tech/compress-pdf Try lossless PDF optimization or create an image-based PDF at a chosen raster resolution and JPEG quality. Lossless mode may retain the existing structure without reducing file size; raster mode changes pages more substantially. Choose according to whether selectable text, links and forms need to remain available in the output. ## Useful tasks - Try reducing a PDF without rasterizing pages - Create a smaller image-based review PDF - Reduce resolution for a short scan-like document ## Steps 1. **Choose a working PDF**: Add one unprotected PDF and consider the features it contains. Decide whether text selection, links or form fields must survive in the copy you are creating. 2. **Choose the compression mode**: Select lossless optimization first when preserving page structure matters. Choose raster mode only when replacing each page with an encoded image is acceptable for the task. 3. **Set raster detail if needed**: For raster mode, choose DPI and JPEG quality and keep the source within twenty pages. Run Process document to create the newly optimized or rasterized PDF. 4. **Compare size and usefulness**: Download the result and check actual file size, text clarity and required interactive features. Keep the original when the compressed copy loses functionality needed elsewhere. ## Settings - **Compression mode**: Choose compression mode according to the result you need. Available choices: LOSSLESS; RASTER. The initial selection is LOSSLESS. - **Raster resolution (DPI)**: Raster resolution (DPI) accepts values from 72 to 200, using whole numbers. The initial value is 120. Change it for a specific output requirement, then check the result before processing more files. - **JPEG quality**: JPEG quality accepts values from 30 to 95, using whole numbers. The initial value is 75. Change it for a specific output requirement, then check the result before processing more files. ## A small review copy of a scan packet A twelve-page scan-like PDF needs a smaller review copy. Try lossless mode first and compare sizes. If necessary, use raster mode at 120 DPI with moderate JPEG quality, then inspect small text and confirm that image-only pages suit the review task. ## Check the result Choose a file, adjust the settings, then download the result. Lossless optimization may not reduce size. Raster mode replaces pages with images and removes text, links and forms. Open the saved output in the app or workflow where you plan to use it. Check one representative result before repeating the same settings with more files. The original files stay unchanged. ## Limits - Files are processed on this device. Browser memory and engine-specific limits apply. Save results before reloading. - Lossless optimization may not reduce size. Raster mode replaces pages with images and removes text, links and forms. - Upload one file with a combined size of at most 100 MB. The completed output must fit within 200 MB. - Files are checked by the local engine; a matching filename alone is not proof of valid contents. - Selections and completed jobs stay available while you navigate inside this tab. Use My files to revisit results. Reloading or closing the tab clears the workspace; download results you want to keep first. ## Questions ### Does lossless mode always reduce size? No. Optimization can reorganize and compress PDF data, but an already efficient document may show little reduction or even a larger output. Compare the reported original and output sizes instead of assuming the mode guarantees a smaller file. ### What does raster mode remove? Raster mode renders each page and replaces its content with a JPEG image. Selectable text, links and form functionality are removed, so use it only when a visual copy is sufficient and retain the original document. ### How many pages can raster mode handle? Raster compression is limited to twenty pages, with a separate rendered-pixel limit per page. Lossless operations use the broader one-hundred-page PDF bound, so the permissible source size depends on the mode you choose. ### How should I choose DPI and quality? Lower DPI reduces page pixel dimensions, while lower JPEG quality adds stronger image compression. Inspect fine text, diagrams and signatures after changing either setting, since a small file is less useful if its necessary details become unreadable. ### Does Compress PDF upload files to another service? Processing runs in this browser, on your device. Files and pasted input are not uploaded to a conversion server. The website and required engine assets must load first; large operations depend on available device memory. ### Can I continue after changing pages? Selections and completed jobs stay available while you navigate inside this tab. Use My files to revisit results. Reloading or closing the tab clears the workspace; download results you want to keep first. ## Related guides - [Merge PDF](https://localconverter.tech/merge-pdf.md) - [Split PDF](https://localconverter.tech/split-pdf.md) - [Images to PDF](https://localconverter.tech/images-to-pdf.md) - [Reorder PDF pages](https://localconverter.tech/reorder-pdf.md) - [PDF to TXT](https://localconverter.tech/pdf-to-txt.md) - [PDF to PNG](https://localconverter.tech/pdf-to-png.md)