Reduce a PDF to 300 KB or as close as possible directly in your browser. Fast, free, and 100% private — no uploads or sign-up required.
Your files are never uploaded to our servers — all compression happens right inside your browser
or pick several files at once from your device
Add your PDF document using the file picker or drag-and-drop area above, then click 'Compress now'. The browser-side target-size engine automatically cycles through multiple rendering scales and JPEG compression passes, continuously testing output sizes until your file reaches 300 KB or smaller.
Results depend heavily on the original document structure, page count, and contents. A 3-page resume with photos can comfortably reach 300 KB, whereas a 200-page scanned textbook or architectural schematic cannot reach 300 KB without severe visual degradation. If the requested target is mathematically unattainable, the tool delivers the absolute smallest file size it can safely produce.
If your selected document is already below 300 KB, our engine detects this instantly and retains the untouched original file. The tool will never artificially re-compress or degrade a document that already satisfies your file size requirements.
Our target-size algorithm uses adaptive multi-pass optimization. It starts with mild compression and only increases downsampling if necessary to satisfy the 300 KB ceiling. Vector typography is preserved whenever possible, ensuring your text remains clear and readable for online forms, email recipients, and printing.
Yes. Kompres PDF provides unlimited free target-size compression directly in your browser with no account creation and no hidden fees.
The objective is to produce a file at or below 300 KB. Depending on the content density and images, the output might be 10% to 20% smaller than 300 KB. If the file is too large to reach the target, the tool gives you the smallest possible output.
No. All target-size analysis, rasterization passes, and PDF rebuilds happen locally inside your web browser. Your private documents never leave your device.