Convert PDF to grayscale
Convert your PDF to black and white — ideal for cheaper, cleaner printing.
How to convert a PDF to grayscale online for free
- 1
Open the color PDF you want to convert
Click Select PDF file and pick the document. The tool reads it locally with pdf.js, checks that it isn't password-protected, and shows a live side-by-side preview of the first page — the original on the left and the grayscale version on the right — so you can see exactly what the finished file will look like before you commit.
- 2
Choose an output quality
The sidebar offers two settings. High quality re-renders each page at 1.5× the page size and encodes the result as JPEG at 0.85 quality — best fidelity, larger file. Smaller file re-renders at 1.2× and encodes at 0.7 — visibly still crisp, noticeably lighter. The grayscale preview updates as you switch, so you're never guessing.
- 3
Click Convert to Grayscale
The tool walks every page in order, redraws it onto an offscreen canvas, applies a true grayscale filter (GPU-accelerated where the browser supports canvas filters, with a manual luminance fallback otherwise), and stitches the results into a fresh PDF with pdf-lib. Progress is reported page-by-page so a long document never looks stalled.
- 4
Download the black & white copy
The success screen shows the before/after file size and, when the conversion also shrank the document, the exact percentage saved. Your download is a standard PDF suffixed -grayscale.pdf. The original file on your disk is untouched — this is a new copy alongside it.
Save ink, shrink scans, print cleaner
Color pages drain the most expensive cartridges on any printer even when the color adds nothing meaningful to the content — a stray header band, a company logo in the corner, a chart no one reads on paper. Converting to grayscale before printing means the printer treats every page as black and white, and the color cartridges stay untouched for the jobs that actually need them.
Colorful scans and photo-heavy PDFs also get significantly lighter as grayscale because each pixel drops from three color channels to one, and pairing this pass with Compress PDF squeezes out the last bit of size for mailbox and portal limits. On top of that, documents simply look cleaner once the stray color casts from phone-camera scans — the yellows, the greens, the blues — are gone and every page reads as neutral, professional black and white.
Private conversion, your documents stay with you
Grayscale conversion is often the last step before a personal document goes somewhere it can't be taken back — a portal upload, a court submission, a scanned ID sent to a landlord. This tool re-renders every page inside your browser tab using pdf.js and pdf-lib, so nothing about the file is transmitted anywhere, and nothing about it is logged on our side.
Once the page has loaded you can disconnect your network and the whole flow — preview, conversion and download — keeps working. The document you convert is the document you keep.
True grayscale output
Every page is redrawn through a real grayscale filter and re-embedded into the new PDF, not just tinted or hidden by a viewer setting. Whichever reader, printer or portal opens the file, the pages arrive as clean black and white — never full-color pixels behind a display trick.
Smaller files
For color scans, phone-camera captures and photo-heavy documents the JPEG re-encode in grayscale usually produces a meaningfully lighter file, and the built-in Smaller file quality trades a little sharpness for extra savings. Text-only PDFs that were already lean won't shrink much, and that's fine — you're doing the conversion for the color, not the size.
Cheaper printing
A grayscale PDF removes any risk of a printer reaching for the color cartridges to render a stray logo, header band or icon. The whole document prints from the black cartridge only, in one predictable pass — no surprise CMYK usage on a hundred-page report.
Cleaner look for scans
Phone-camera scans usually come out with a yellow cast from indoor light, a green cast from fluorescent tubes, or a blue cast from a screen glow. Grayscaling collapses all of that into neutral tones, and the finished document looks like it came off a real flatbed scanner instead of a kitchen table.
When do you need a grayscale PDF?
Printing long documents where color adds nothing
Textbooks, meeting packs, contracts, study notes and internal reports rarely need color to be understood, but color cartridges are the most expensive consumable on any office printer. Convert the file to grayscale first and the printer treats every page as black and white — no accidental color hits on a page you're going to staple and forget.
Submitting documents to portals that require black & white
Government submissions, court filings, tender responses and some university portals explicitly ask for black-and-white PDFs, and reject uploads that contain color pages. Converting the file here means you send exactly what they asked for, once, instead of getting the submission bounced back a day later.
Shrinking colorful scans before emailing or uploading
A scanned brochure or a photo-heavy report can push past mailbox and portal limits. Grayscale re-encoding usually knocks a noticeable chunk off the size, and pairing this with a follow-up pass through Compress PDF (linked below) gets you the smallest possible file without touching the page dimensions.
Making phone-camera scans look like proper scans
A snap of a receipt or a contract on a desk tends to look amateur — uneven lighting, a color tint, a warm cast from the room. Converting that PDF to grayscale strips the color noise and produces something that reads and prints like a document, not a photo of a document.
Frequently asked questions
How do I convert a PDF to black and white for free?+
Click Select PDF file, pick your document, choose High quality or Smaller file in the sidebar, then click Convert to Grayscale. The tool re-renders every page in grayscale and hands back a copy named -grayscale.pdf. No signup, no upload, no watermark, no page limit.
Will grayscale make my PDF smaller?+
Usually yes for colorful documents, scanned pages and photo-heavy PDFs — the JPEG re-encode in grayscale drops each pixel from three channels to one, and the success screen shows the exact percentage saved. Text-only PDFs that were already efficient can come out about the same size or slightly larger, because the conversion still rasterizes each page. If size is your priority pick Smaller file, then run the result through Compress PDF.
Will the text stay sharp?+
Yes, at both quality settings the text remains clearly legible on screen and in print. High quality re-renders pages at 1.5× the page size and encodes as JPEG at 0.85 — visually indistinguishable from the original for reading. Smaller file uses 1.2× and JPEG 0.7 to save space, which is still crisp for standard document text; if you plan to print at very large sizes or read very small footnotes, keep the High quality setting.
Can I still select or copy text after conversion?+
No. To guarantee identical black-and-white output in every reader and printer, the tool rasterizes each page — the finished PDF stores each page as a grayscale image rather than as searchable text characters. Keep your original file if you'll still need to select, copy or search the text; use the grayscale copy for printing, sending or submitting.
Do my files get uploaded to a server?+
No. The scan, the previews, the page-by-page grayscale render and the writing of the final -grayscale.pdf all happen inside your browser tab using pdf.js and pdf-lib. Nothing about the file is transmitted to us or to any third party, and once the page has loaded the whole flow keeps working with your network disconnected.
Is grayscale the same as printing in black-and-white mode?+
No — they're related but different. A printer's black-and-white mode drops color at print time only, on that one printer, for that one job; the file itself is still a full-color PDF, and the next person who prints it can (and often will) print it in color again. Grayscaling here converts the file itself, so every reader, printer, portal and email preview shows the document in black and white from now on.
Can I convert only some pages?+
Not in this tool — the conversion always applies to every page in the document. If you need one section grayscale and another in color, split the file with Split PDF first, convert only the grayscale section here, then merge the pieces back together with Merge PDF.
Can I convert scanned or photo-heavy PDFs?+
Yes — that's the most common use of this tool. Scanned brochures, camera-captured contracts, photo reports and image-heavy handouts all convert cleanly to grayscale, and these are precisely the files where you'll see the biggest visible improvement and the biggest file-size reduction.
Can I undo the conversion?+
The tool never overwrites your original — the grayscale copy is a new file suffixed -grayscale.pdf, saved alongside the source. There's no in-tool undo because there's nothing to reverse: if you don't like the result, delete the copy, reopen the original and try again with the other quality setting.
Do I need Adobe Acrobat?+
No. The tool is a web page that runs in Chrome, Safari, Firefox, Edge or Brave with no Acrobat licence, no install and no account. The output is a standard, universally-readable PDF that any viewer or printer will accept.