Need to hide a name or phone number before you share a PDF? The Redact PDF tool finds the words you type and covers them with black boxes. It then rebuilds every page as a picture, so the hidden text is gone.
It suits office staff, students, and freelancers who share letters, forms, or reports. The trade is real: you get true removal, but the new file has no selectable text at all. Read the sections on limits before you share anything sensitive.
Table of Contents
- What the Tool Does
- How to Use It, Step by Step
- How It Works
- Example: An Employee Letter
- What You Get and What You Lose
- Checking Your Result
- Limitations to Know
- FAQs About Redact PDF
What the Tool Does
The tool searches the text layer of your PDF and draws a solid black box over each match.
- Select PDF File: opens the file picker. The name appears under it, or "No file selected".
- Text to Black Out (Not Case Sensitive): a box where you type one word or phrase per line.
- Notice box: a yellow warning above the button that explains the picture rebuild.
- Auto-Redact & Download: starts the search, covers the matches, and builds the new file.
- Progress bar: shows "Scanning PDF..." and then "Processing page 1 of 3..." style updates.
- Download Redacted PDF: the link that appears when the work ends.
- Start New: reloads the page.
How to Use It, Step by Step
- Click Select PDF File and choose your PDF.
- Type each term you want covered on its own line. Capital letters do not matter.
- Press Auto-Redact & Download. The button shows "Processing..." while it works.
- When the green "Done." line appears, click Download Redacted PDF.
- Open the file, which is named AskWebTools, then your file name, then redacted. Check every page before you share it.
How It Works
The tool draws each page with pdf.js and reads its text pieces. It looks for your terms inside each piece, ignoring capital letters and extra spaces around your terms. On the drawn page, it paints a black box over only the matched characters, with a small margin.
It then saves each page as a JPEG image and builds a brand new PDF from those images. Each page keeps its original size in points. The old text layer is never copied into the new file.
Choose PDF→Type Terms→Draw Pages And Black Boxes→Rebuild As Images→Download Redacted PDF
The work happens in your browser. The code reads the file locally and builds the new PDF in memory. It sends the file nowhere, so it is not uploaded. The pdf.js and pdf-lib code libraries load from public content networks when the page opens.
Example: An Employee Letter
Hannah works in HR. She has a one-page letter that names "Jane Doe" and lists the phone number "555-0142". She wants to share a version that hides both.
She selects the PDF and types jane doe on line one and 555-0142 on line two. She presses Auto-Redact & Download. The page shows "Done. Covered 2 matches on 1 page. All 1 page is now images with no selectable text. Open the file and check every page before sharing it".
The saved copy shows black bars over the name and the number only. The rest of the line, such as "Employee:", stays visible. When she tries to select text in the new file, nothing highlights.
What You Get and What You Lose
The big gain is that the covered words are truly removed. Search and copy tools find no text on any page of the result. Every page becomes a picture, including pages with no match.
The cost is real too. Pages are drawn at about 144 DPI as JPEG, so the file can grow and fine text may look softer. Links, bookmarks, comments, and form fields from the original are not carried over.
The tool only finds text that sits in the PDF text layer. If a name also appears inside a photo or logo, no box covers it.
Checking Your Result
Open the file and look at every page, because there is no preview before you download. Try to select text with your mouse. You can also run the file through PDF to Text, which should return nothing useful.
Scanned PDFs have no text layer, so this tool cannot search them. It shows a message and creates no file. Use text extraction with OCR to learn what a scan contains.
Look at the file properties with the PDF metadata viewer. If the output is large, shrink it with Compress PDF. More tools are in the PDF tools hub.
Limitations to Know
- A term split across two lines or text pieces may be missed.
- Box width inside a line is estimated from character widths, so check the edges.
- If nothing matches, you see "None of your terms were found in the text of this PDF". No file is made.
- A scan with no text layer shows "No text layer was found in this PDF". No file is made.
- A locked or damaged PDF shows "This PDF could not be processed".
- With no file chosen, you see "Please choose a PDF file first".
- With empty terms, you see "Please enter text to redact".
- There is no manual drawing, no image redaction, and no batch mode.
- Very large pages are drawn at a smaller scale, so detail drops.
FAQs About the Redact PDF
Does Redact PDF upload my file?
No. The code processes the PDF in your browser and does not send it to a server. Only the libraries load from the web.
Does it remove the text under the black boxes?
Yes. Each page becomes an image, so the original text is not in the new file. Still, open the result and check every page.
Is "Jane" different from "jane"?
No. Matching ignores capital letters, and it trims spaces around each line. Blank lines and repeated terms are skipped.
Can I redact a scanned PDF?
Not with this tool. It searches text, and scanned pages hold only pictures of words.
Can I draw boxes by hand on the page?
No. The only control is the list of terms. There is no tool for drawing on the page.
Why is my redacted file bigger?
Every page is stored as a JPEG picture instead of compact text. Try a compression tool if you need a smaller file.
This tool runs in your web browser and may not handle every PDF file, font, or browser the same way. Keep a backup of your original file. Reviewed for general accuracy by Prof. Dr. Khalil Mudassar, PhD.