Compress a PDF to an exact size
Need it under 100KB, 200KB, or 2MB? Set the limit and get the best quality that fits. Everything happens in your browser, so your file is never uploaded.
Drop your PDF here
or tap to choose a file · stays on your device
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Your file has not left this device.
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Download compressed PDFHow it works
Your browser downloads a compression engine: Ghostscript, the same software print shops and publishers have relied on for decades, compiled to WebAssembly. It rebuilds your PDF locally, re-encoding the images inside it at lower resolution while leaving text sharp.
When you set a size limit, the engine runs several passes at different quality levels and keeps the best-looking result that fits under your number. That is the whole trick: you get the maximum quality your size limit allows, not a one-size-fits-all preset.
Because the work happens on your device, there is no upload, no queue, no server storing your document, and no file-deletion policy to trust. There is simply nothing to delete.
Questions
How does compressing to an exact size work?
SquashTools runs several compression passes at different quality levels and keeps the highest-quality result that fits under your limit. You get the best possible version of your PDF that still meets the size requirement, not just a generic "medium" preset.
Is my PDF uploaded to a server?
No. The compression engine (Ghostscript, compiled to WebAssembly) runs inside your browser. Your file never leaves your device. We could not see it even if we wanted to. Once the page has loaded, compression works offline too.
Will my PDF lose quality?
Compression works mainly by re-encoding images inside the PDF at lower resolution. Text stays sharp because it is not an image. The lower your size limit, the softer photos and scans will look. The tool always keeps the highest quality that fits.
Is there a file size limit?
Processing happens in your device’s memory, so very large files depend on your hardware. Files up to around 100MB work well on a typical laptop or phone; a huge scanned archive may struggle on older devices.
Can I combine several PDFs first?
Yes. The merge tool joins PDFs into one document, also entirely in your browser, and you can then bring the result back here to compress it. Merging on its own does not change file size, since pages are copied rather than re-encoded. Merge PDF files.
Why is this free?
Because it costs us almost nothing to run. There is no server doing the work: your device does it. No account, no watermark, no per-day limits.