Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / PDF Tools / PDF to Grayscale

PDF to Grayscale

Convert color PDFs to grayscale or high-contrast black & white.

Free, no uploads, no sign-up. Runs 100% in your browser.

How PDF to Grayscale works

PDF to Grayscale runs entirely in your browser. Convert color PDFs to grayscale or high-contrast black & white. Under the hood it uses pdf-lib (a pure-JavaScript library that creates and edits PDF structure (pages, text, images, forms)) and PDF.js (Mozilla’s PDF renderer, used for thumbnails, previews and text extraction (runs in a Web Worker)). Your files are read into this tab’s memory, processed on your own CPU, and handed back to you as a download. Nothing is sent to a server.

Input: PDF.

How to use PDF to Grayscale

Drop your PDF onto the PDF to Grayscale area, or click to choose it.
Wait a moment while page thumbnails render locally.
Choose the pages and options you need. Previews update as you go.
Press the main action button and download the finished PDF.

Tips

Encrypted PDFs must be unlocked first with Unlock PDF.
Large scanned PDFs are mostly images. Compress PDF shrinks them the most.
Your original file is never modified; you always download a new copy.

PDF to Grayscale FAQ

Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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Split PDF: Split by ranges, every N pages, or extract each page into a ZIP.
Compress PDF: Shrink PDF size with smart image downsampling and stream compression.
Sign PDF: Draw, type or upload a signature and place it anywhere, plus dates and initials.