Uwarp

Drag on the page to place a black redact box. Boxes cover the preview visually; download to stamp them into the PDF. This is a visual cover, not certified secure redaction.

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Redact PDF with a black box

Draw a redact box on a PDF page in your browser. Cover sensitive spots with black bars, download locally. Free, no sign-in.

What is a PDF redact box?

A redact box is a solid cover—usually black—drawn over part of a PDF page to hide text or images. People search for “redact box” when they need to mask sensitive spots before sharing. This free local-first tool lets you drag boxes on a preview and stamp them into the PDF; it is a visual cover, not certified secure redaction that removes underlying content.

Redact PDF features

Cover spots with a black redact box.

  • Drag a redact box

    Draw black bars directly on the page preview.

  • Multi-page

    Move between pages and add more boxes.

  • Local-first

    Stamping stays in the browser.

  • Free

    No account required.

How to redact a PDF

Three steps to cover sensitive spots.

  1. Upload

    Drop an unlocked PDF.

  2. Draw boxes

    Drag on the page to place black covers.

  3. Download

    Apply boxes and save the PDF.

Tips

Safer everyday covering.
  • 01

    Overlap a little

    Make boxes slightly larger than the text you want covered.

  • 02

    Not for legal discovery

    Use a dedicated redaction workflow when content must be permanently removed.

  • 03

    Need to add text instead?

    Use Edit PDF for white-box overlays and new wording.

Great for

Quick visual covers.

  • Sharing drafts

    Hide an address or ID before you send a scan.

  • Screenshots into PDF

    Cover a name that should not stay visible.

  • Classroom handouts

    Mask answers before printing.

Why redact PDF here

Fast local black-box covering.

  • Free

    Draw redact boxes with no signup.

  • Local-first

    Your PDF stays on the device.

  • No watermark

    Clean PDF downloads.

Technical notes

How redaction works here.
Drawing
pdf-lib black rectangles on selected pages.
Preview
pdf.js page render with overlay boxes.
Limits
Up to 20 MB and 30 pages.
Privacy
Client-side only—no network upload.

Sources & References

References on PDF graphics and redaction limits.
  • “Path objects are used to paint shapes such as lines, curves, and rectangles.”
    — Adobe PDF Reference

    PDF graphics: Redact boxes are filled rectangles drawn on the page content stream. opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf

  • “Create and modify PDF documents in any JavaScript environment.”
    — pdf-lib documentation

    pdf-lib: Black rectangles are stamped with pdf-lib drawRectangle. pdf-lib.js.org/

Frequently Asked Questions

Quick answers about this tool—open a question to read more.