PDkefCompress PDFOn-device

Compress PDF Free: No Limits, Runs Locally

Shrink your PDF's file size instantly, even down to a target like 100KB for strict portal upload limits on tax records, applications, and scanned IDs.

Star us on GitHubMIT licensedRuns in your browser

Drop PDF here

Private. Files never leave your device.

How it works

How to compress a PDF online for free

Reduce the file size of your PDFs, right in your browser. No upload, no server. Your files never leave your device.

  1. Upload your PDF. Select or drag-and-drop the file you want to compress.
  2. Choose a mode. Pick a quality preset (Extreme, Recommended, or High Quality), or select Target Size and enter a specific limit like 100 KB, 200 KB, or 1 MB.
  3. Compress and download. Click Compress PDF, review the size savings shown, and save your compressed file.

Free for everyone

Shrink PDFs to a target like 100KB for strict portal limits as many times as you need, with no watermark or daily cap. Because compression runs on your device, there's nothing to upload and no server cost to pass on to you.

It's open source under the MIT license, so anyone can read the code, fork it on GitHub, or share it. Simple PDF tools should be free for everyone.

Got questions?

Frequently asked questions

Can I compress a PDF to exactly 100KB?

Yes. Select the "Target Size" option, enter 100 in the KB field (or click the 100 KB quick-pick), and click Compress. The tool automatically searches for the highest image quality that fits the target, stepping down the resolution only as far as needed. Quick-pick presets for 100 KB, 200 KB, 500 KB, and 1 MB are provided for common portal limits.

How does the target size compression work?

The tool rasterizes each PDF page to a canvas, then binary-searches JPEG quality settings until the total output size fits your target. It tries the highest resolution first and only drops DPI if the minimum JPEG quality still exceeds the budget - so you always get the best possible quality that fits. Everything happens locally in your browser; no file is ever uploaded.

Is the PDF compression secure?

Yes. Compression is 100% client-side and runs entirely in your browser. Your files - and any sensitive content like tax records, scanned IDs, or contracts - are never uploaded to any server.

What is the difference between the compression levels?

Extreme compression reduces file size by 60-80% using 72 DPI images. Recommended compression reduces size by 40-60% at 110 DPI. High Quality compression reduces size by 10-30% at 150 DPI. The Target Size option lets you name a specific byte limit and the tool finds the best quality that fits.

Does compressing a PDF affect text search or copying?

Yes. To compress client-side, pages are rasterized into images. Text selection, copy-pasting, and embedded links will be disabled in the output. This trade-off is necessary for any browser-based compressor that achieves real file size reduction.

Is there a limit on the file size I can compress?

No artificial limit - no daily task cap, no watermark, no paywall. Most online compressors impose limits because server processing costs them money. This tool runs entirely on your device, so the only constraint is your device's available memory.