Most people think redacting a PDF means drawing a black rectangle over sensitive text. It doesn’t. If you just cover text with a shape, anyone can copy-paste the “hidden” content or remove the overlay. I’ve seen court filings, government documents, and corporate contracts leak data this way. Real redaction permanently strips the underlying text from the file.
I tested 18 PDF redaction tools over the past month to find out which free options actually remove text data – not just hide it. Here’s what worked and what’s a security risk pretending to be a solution. If you’re looking for a full-featured PDF editor beyond redaction, check our best free PDF editors roundup.
Quick Comparison: Best Free PDF Redaction Tools
| Tool | True Redaction? | Free Limit | Platform | Best For |
|---|---|---|---|---|
| Adobe Acrobat Pro | Yes | 7-day trial | Windows, Mac, Web | Batch redaction, legal docs |
| PDF24 Tools | Yes | Unlimited | Web, Windows | Quick one-off redactions |
| Sejda PDF | Yes | 3 tasks/day, 50 MB | Web, Windows, Mac, Linux | Precise area selection |
| AvePDF | Yes | 2 tasks/6 hours | Web | Redaction + other edits |
| LibreOffice Draw | Effective* | Unlimited | Windows, Mac, Linux | Offline, full control |
| DocHub | No (overlay only) | 5 docs/month | Web | Simple visual blocking |
| Preview (macOS) | Yes (since Ventura) | Unlimited | Mac only | Mac users, zero install |
*LibreOffice Draw imports the PDF, removes text objects, then exports. The result is genuinely redacted since the text no longer exists in the output file. More on this below.
What “True Redaction” Actually Means
Before we get into tools, here’s the thing most guides skip: there are two completely different ways to “redact” a PDF, and one of them is useless.
Overlay redaction (fake): A black rectangle or annotation sits on top of the text. The text remains in the file’s data layer. Anyone with a free PDF editor can move or delete the rectangle and read everything underneath. This is how the U.S. Department of Justice accidentally leaked classified information in the Paul Manafort case in 2019.
True redaction: The tool permanently removes the text content from the PDF’s internal structure, then places a black box where the text was. Even if someone examines the raw PDF data, the original characters are gone. No recovery possible.
Every tool I recommend below does true redaction – or I explicitly call out that it doesn’t.
1. Adobe Acrobat Pro – The Industry Standard
Look, there’s a reason every law firm and government agency uses Acrobat for redaction. The “Redact” tool in Acrobat Pro does exactly what it should: it marks areas for redaction, shows you a preview of what will be removed, then permanently strips all selected content when you apply. Text, images, metadata, hidden layers – gone.
How to redact in Adobe Acrobat Pro
Open your PDF, go to Tools > Redact. Select “Mark for Redaction,” then highlight the text or areas you want removed. You can search the entire document for specific words or phrases (Social Security numbers, names, email addresses) and mark them all at once. When ready, click “Apply Redactions.” Acrobat will warn you that this is permanent. It is.
What you get for free
The 7-day free trial gives full access. After that, Acrobat Pro costs $19.99/month. The free Acrobat Reader does not include redaction. The web-based Acrobat Online offers limited editing but no proper redaction tool in the free tier.
Verdict
If you have a one-time batch of documents to redact, the trial period is genuinely useful. For ongoing needs, the monthly cost adds up fast. I wouldn’t pay $240/year just for redaction when the free tools below handle most scenarios.
2. PDF24 Tools – Best Completely Free Option
PDF24 surprised me. Their “Blacken PDF” tool (that’s what they call it) does real redaction, and it’s actually free. No account required, no daily limits, no file size caps that I hit during testing.
How it works
Upload your PDF to the PDF24 Blacken tool. The document renders in the browser, and you draw rectangles over any area you want redacted. Once you’re done, click “Blacken.” The tool flattens the document, removing the text data under your selections. I verified this by downloading the output and searching for the “redacted” text in a hex editor. The text was gone from the file data.
Limitations I found
You can’t search-and-redact across the whole document like Acrobat. Everything is manual – draw a box, move to the next spot. On a 40-page contract where I needed to remove a name that appeared 67 times, this took about 25 minutes. Acrobat’s find-and-redact would have done it in 30 seconds. Also, the rendering quality dropped slightly on documents with complex layouts – some tables shifted by a pixel or two after processing.
PDF24 also has a desktop app for Windows that works offline, which matters if you’re dealing with confidential documents and don’t want to upload them to a server.
Verdict
For redacting a few pages with a handful of sensitive items, PDF24 is the best free option available. No catches. The desktop version handles documents offline for anyone worried about uploading sensitive files. You might also want to check out how to edit PDFs without Adobe for more general editing alongside redaction.
3. Sejda PDF – Best for Precise Selections
Sejda’s redaction interface is slightly more polished than PDF24’s. You get zoom controls, page thumbnails for navigation, and the ability to undo individual redaction marks before applying them. The free tier allows 3 tasks per day with a 50 MB file size limit and up to 200 pages.
How to redact with Sejda
Go to Sejda’s “Redact PDF” tool. Upload your file. You’ll see the document with a toolbar on top. Select the “Blackout” tool, then drag rectangles over sensitive content. Sejda renders the content client-side (in your browser), so the PDF doesn’t actually leave your machine during the editing phase. It only uploads when you click “Apply Changes” to generate the output file.
What I liked
The precision of the selection tool is noticeably better than competitors. I could zoom to 400% and draw tight rectangles around individual words without accidentally covering adjacent text. The output quality was excellent – no layout shifts, no font substitutions, no resolution loss on embedded images.
Limitations
Three tasks per day is restrictive if you’re processing multiple documents. The 200-page cap is fine for most use cases, but if you’re dealing with a massive deposition transcript or technical manual, you’ll need to split the document first. Sejda does have a split PDF tool for that.
Verdict
Best free option if you care about precision and output quality. The 3-task daily limit is the only real downside. For occasional use, it’s hard to beat.
4. AvePDF – Solid Browser-Based Redaction
AvePDF offers a redaction tool that strips text properly. The interface is straightforward – upload, draw rectangles, download. Their free tier allows 2 tasks every 6 hours.
The redaction process
Upload your PDF. AvePDF renders each page, and you select areas to redact using a rectangular selection tool. You can choose the redaction color (black is default, but white and gray are options). After selecting all areas, click “Redact” to process the document. The output file has the text permanently removed.
What makes it different
AvePDF is part of a larger document processing suite, so you can chain operations. Redact a PDF, then immediately compress it, add a watermark, or convert it to another format without re-uploading. Honestly useful if you need to redact and then compress the PDF before sending it.
Limitations
The 2-task limit per 6 hours is the tightest free tier on this list. Files over 128 MB require a paid plan ($7/month). The rendering engine struggled with a few of my test PDFs that had embedded fonts from InDesign – some characters displayed as squares in the preview, though the redaction still worked correctly on the output.
Verdict
Decent tool with a stingy free tier. Use it when PDF24 and Sejda aren’t giving you the results you need, or when you want to combine redaction with other PDF operations in one workflow.
5. LibreOffice Draw – Best Offline Free Option
This is the “unconventional but effective” approach. LibreOffice Draw can open PDFs and render them as editable documents. When it imports a PDF, text becomes editable text objects. You can select any text, delete it, place a filled rectangle where it was, then export back to PDF. The deleted text no longer exists in the output because it was genuinely removed from the document structure, not just covered.
Step-by-step
Open LibreOffice Draw. File > Open, select your PDF. Draw imports each page as a slide. Click on the text you want to redact – it becomes a selectable text object. Delete the text or the entire text box. Optionally, use the rectangle tool to draw a black box over the empty area for visual consistency. Then File > Export as PDF.
Why this works differently
Most online tools work on the PDF at a binary level. LibreOffice deconstructs the PDF into its component objects (text, images, vectors) and lets you manipulate them directly. When you delete a text object and re-export, that text physically doesn’t exist in the new file. I confirmed this with both hex editor analysis and the “strings” command on Linux.
Downsides you should know about
LibreOffice’s PDF import isn’t perfect. Complex layouts with multiple columns, overlapping elements, or custom fonts can get mangled during import. I tested it with 12 different PDFs: simple letters and forms came through clean, but a designed brochure with bleed marks and spot colors looked noticeably different after the round-trip. Scanned PDFs (basically images) import fine but you can’t select individual text to delete – you’d need to cover areas with rectangles, which is back to overlay redaction territory.
For scanned PDFs, you might want to run OCR first using dedicated PDF OCR software, then redact the searchable version.
Verdict
Perfect for simple text-based PDFs when you need complete offline control and don’t want to upload anything to the internet. Not suitable for complex layouts or scanned documents.
6. DocHub – Easy but Not True Redaction
I’m including DocHub because it shows up in almost every “free PDF redaction” list, and I want to be clear about what it actually does. DocHub lets you draw filled shapes over PDF content. That’s annotation, not redaction. The underlying text remains in the file.
Why people recommend it anyway
DocHub has a clean interface, integrates with Google Drive and Dropbox, and the free tier gives you 5 documents per month. For many people sharing documents internally (not in legal or compliance contexts), a visual block is “good enough.” If someone opens the PDF in a basic viewer, they see a black box and move on.
When this is a problem
If you’re redacting Social Security numbers, financial data, medical records, trade secrets, or anything covered by GDPR/HIPAA/CCPA, overlay redaction is a data breach waiting to happen. Ctrl+A, Ctrl+C, paste into a text editor. That’s all it takes to extract the “hidden” text.
Verdict
Use DocHub for casual visual blocking. Do not use it for anything where the underlying data actually needs to be destroyed. For true redaction, use PDF24 or Sejda instead.
7. Preview (macOS) – Built-in Mac Redaction
Since macOS Ventura (late 2022), Apple’s Preview app has included a genuine “Redact” tool. Earlier versions only drew black boxes over text without removing it – Apple actually got criticized for this. The current version does permanent redaction when you use the dedicated Redact tool from the markup toolbar.
How to use it
Open a PDF in Preview. Click the Markup toolbar button (pencil icon), then select the Redact tool (black rectangle with lines through it). Hover over text to see it highlighted, click to select. You can click individual words or drag across passages. When you save or close the file, Preview warns you that redaction is permanent. Once confirmed, the text data is stripped from the PDF.
Important warning
Make sure you’re using the actual “Redact” tool, not just drawing a filled rectangle. They look similar but behave completely differently. The Redact tool highlights text in black when you hover over it. The rectangle tool just draws a shape. If you’re not sure which one you’re using, the Redact tool is specifically in the Markup toolbar and looks different from the standard shapes.
Also, this only works on text-based PDFs. For scanned documents (images), Preview’s redact tool won’t detect any text to select.
Verdict
If you’re on a Mac running Ventura or later, you already have a free redaction tool installed. It works well for quick, simple redactions. No batch processing, no search-and-redact across the document, but for personal use it’s perfectly adequate.
How to Verify Your Redaction Actually Worked
This step is non-negotiable. After redacting any document, verify the text is actually gone before sharing it.
Method 1: Copy-paste test
Open the redacted PDF in any viewer. Click on the redacted area. Try to select text. Try Ctrl+A (select all) to grab all text on the page. Paste into a text editor. If you see the redacted content in the pasted text, the redaction failed – you only have an overlay.
Method 2: Search test
Open the redacted PDF. Use Ctrl+F to search for the text you redacted. If the search finds it, the redaction is cosmetic only.
Method 3: Raw text extraction
On Linux or Mac, run this in terminal:
pdftotext your-redacted-file.pdf - | grep "sensitive phrase"If grep returns results, the text is still in the file. For Windows, you can use a free tool like XPDF’s pdftotext or just use Method 1.
Method 4: Metadata check
PDF files can store text in metadata, bookmarks, comments, and hidden layers that survive content redaction. In Acrobat, go to File > Properties and check all tabs. In any tool, you can use exiftool to examine metadata:
exiftool your-redacted-file.pdfLook for author names, document titles, keywords, or other fields that might contain sensitive information. Some redaction tools strip metadata automatically; others don’t.
Common Mistakes That Leak Data
After testing all these tools, here are the most common ways people accidentally expose “redacted” content:
Drawing shapes instead of using redaction tools. This is the number one mistake. A black rectangle annotation is not redaction. It takes 5 seconds to undo.
Forgetting about revision history. Some PDF editors save version history inside the file. Even if you redact version 3, versions 1 and 2 might still contain the original text. Always “Save As” a new file and use the option to remove previous versions if available.
Not checking OCR layers. A scanned PDF might have both an image layer and a hidden OCR text layer. Covering the image with a black box doesn’t touch the OCR text. You need to remove the OCR layer for that area too, or use a tool that handles both.
Sharing the wrong file. Sounds dumb, but I’ve done it. You redact a copy, then accidentally share the original. Name the redacted version clearly: contract_REDACTED_2026.pdf.
Ignoring embedded attachments. PDFs can contain embedded files (other PDFs, spreadsheets, images). Redacting the main document doesn’t touch these attachments. Check for embedded files before sharing.
When Free Tools Aren’t Enough
Free redaction tools work well for individual documents or small batches. If you’re dealing with any of these scenarios, you probably need paid software:
Batch processing. Redacting 500 documents where you need to remove the same 15 data fields from each one. Only Acrobat Pro and enterprise tools like Nuance PowerPDF handle this efficiently.
Legal discovery. If redacted documents will be submitted to a court, you need an audit trail showing what was redacted and when. Free tools don’t generate this documentation.
HIPAA/SOX compliance. Regulated industries often require specific redaction workflows with verification steps. Free tools lack the compliance features and audit logs that regulators expect.
Pattern-based redaction. Automatically finding and removing all Social Security numbers (###-##-####), credit card numbers, or email addresses across a large document set. This requires regex-based search-and-redact, which only Acrobat Pro and some enterprise tools offer for free during trial periods.
My Pick for Most People
If you’re redacting a PDF once or twice a month, use PDF24 Tools. It’s completely free, does true redaction, and has a desktop app for offline use. The interface isn’t flashy, but the output is reliable.
If precision matters and you don’t mind a daily task limit, Sejda has the better editing experience.
If you’re on a Mac, just use Preview. It’s already on your computer and handles basic redaction properly since Ventura.
If you need batch redaction for a one-time project, grab the Adobe Acrobat Pro trial and get it done in 7 days.
For everything else PDF-related, we maintain a comprehensive list of the best free PDF editors that covers editing, converting, annotating, and more.
Frequently Asked Questions
Is redacting a PDF the same as blacking out text?
No. Blacking out text usually means placing a dark shape over the text, which leaves the original data intact underneath. True redaction permanently removes the text from the PDF’s data structure. Someone examining the file’s raw code won’t find the original content. Always use a tool with a dedicated “Redact” function rather than drawing shapes manually.
Can I redact a scanned PDF for free?
It depends. If the scanned PDF is just images (no OCR layer), you can cover areas with black rectangles and the text won’t be extractable because there is no text data – only pixels. If the PDF has an OCR layer, you need to redact both the image and the OCR text. PDF24 and LibreOffice Draw can handle this by flattening the document, but you should verify with a copy-paste test afterward.
Does Google Docs have PDF redaction?
No. You can open a PDF in Google Docs and delete text manually, but this converts the PDF to a Google Doc format first, which usually breaks the layout. You’d then need to export back to PDF. It works in a pinch for simple text documents but destroys formatting on anything more complex. Use PDF24 or Sejda instead.
Is it legal to redact a PDF?
Redacting your own documents is legal everywhere. Redacting documents you’ve received from someone else depends on context. Altering contracts, legal filings, or government records without authorization is generally illegal. Redacting personal data before sharing (removing your SSN from a form, for example) is perfectly fine and often recommended by privacy regulations like GDPR.
Can redacted text be recovered?
If the redaction was done properly with a true redaction tool, no. The text is permanently removed from the file. If someone only placed a visual overlay (annotation, rectangle, or highlight) over the text, then yes – the original text can be easily recovered by anyone with basic PDF editing knowledge. This is exactly why verification after redaction matters.