Compress PDF
Reduce PDF file size in your browser, or compress to a target size in KB. Free online PDF compressor — no upload to servers, no registration required.
How to use Compress PDF
- Upload your PDF — Click the upload area or drag and drop your PDF file. There is no fixed size limit.
- Choose a level, or a target size — Select Low for a lossless pass that keeps text selectable, or Medium or High to re-render pages as images for a much smaller file. To hit a hard limit instead, switch to To a target size and type the cap in KB.
- Compress the file — Click Compress PDF. The tool processes your file entirely in your browser — nothing is uploaded to any server.
- Download the result — Once compression is complete, click Download to save the smaller PDF to your device.
Frequently asked questions
- Can I compress a PDF to a specific size?
- Yes. Switch the mode to To a target size and enter the limit in KB, so 200 for a 200 KB cap. The tool compresses, measures the result, and re-renders at lower settings until the file fits, up to five passes. If it cannot reach your number it says so and hands back the smallest version it managed, rather than a file that is still over the limit.
- Can I compress a PDF to 100KB?
- Often, but not always, and it depends on what is inside the file. Scanned pages and photo-heavy PDFs usually reach 100 KB because the images can be re-rendered at a lower resolution. A long text PDF may not: converting text pages to images can make the file larger, not smaller, and the tool will tell you that instead of pretending it worked. Splitting the document or deleting pages is the reliable way down from there.
- Does compressing a PDF reduce its quality?
- It depends on the level. Low is lossless: it re-saves the PDF with object-stream compression, keeps the text selectable, and how much it saves depends entirely on how the file was produced. Measured through this tool: three LaTeX-produced papers dropped 14.44%, 17.60% and 23.44%, while five papers that had already been run through an optimiser came back 0.04-0.47% larger, and a 300 DPI scan moved -0.04%. All of them already used object streams, so that is not the difference — the producer is. Medium and High re-render each page as a JPEG at 144 or 96 DPI, which is where the 50-85% reductions come from, but the text becomes part of the image and is no longer selectable or searchable. Pick Low when the text layer matters.
- Can I compress a PDF without losing any quality?
- Use the Low level. It rewrites the file structure more efficiently without touching the page content, so nothing is re-encoded and nothing is degraded. The trade-off is that the saving is unpredictable: measured between a 23.44% reduction and a 0.47% increase, depending on how the file was produced. It costs nothing to try, since the pages are untouched either way. If Low does not shrink your file enough, Medium, High or a target size will.
- Is there a file size limit for the PDF compressor?
- There is no fixed limit. All processing happens in your browser, so the practical limit is your device's memory, and your file is never uploaded to any server.
- How much can I reduce a PDF file size?
- Typical size reductions range from 30% to 90% depending on the content. PDFs with many high-resolution images see the greatest savings.
- Is the PDF compressor really free?
- Yes. The compressor is completely free with no registration, no daily limits, and no hidden fees.
- Can I compress multiple PDFs at once?
- Currently you can compress one PDF at a time. Upload your file, choose your compression settings, and download the result.