How to Black Out a Social Security Number on a PDF

You need to send a tax form, a job application or a lease form. It has your Social Security number (SSN) on it, and the person you're sending it to doesn't need it. So you want to black it out.

The tricky part: many ways of blacking out a PDF only cover the number. It is still in the file, and anyone can copy it out. This guide shows safe ways to do it, and a quick test to make sure it worked. The easiest safe way is TrueRedact, which works in your web browser and keeps your file on your computer.

First: do they need it at all?

Ask before you send. Some offices need your full SSN, for example for tax or payroll forms. Many others don't. If they don't need it, black it out. If they only need some pages, you can also send just those pages (see the tips below).

Why a black box is not enough

In most PDF apps, a black box or a black highlighter is a shape sitting on top of the page. The words underneath are still there. Someone can:

Drag across the black box and copy the number.
Search the file for the number and find it.
Move the box out of the way.

To be safe, the number has to be taken out of the file, not just covered.

Way 1: TrueRedact (safe and quick)

TrueRedact takes the words out of the page. Your PDF is opened and changed inside your browser, and it never leaves your device.

Go to tools.ltd/trueredact.
Click Choose a PDF, or drag your PDF into the box.
TrueRedact already looks for Social Security numbers, plus account and card numbers, emails and phone numbers. Want to hide your name too? Type it in the box, one name per line. Names are not found on their own.
Press Hide and check.
TrueRedact blacks out each one and takes the words out. Then it searches the new copy for every word you picked. You only get the download if none are found.
Look at the preview, then download your safe copy.

Good to know: pages with something hidden are turned into pictures with black bars. That's how the words are removed. You can't select words on those pages anymore. Pages with nothing hidden stay the same. TrueRedact can't read scans or photos.

Way 2: Print, marker and scan (free, no software)

This old-fashioned way works if you're careful. It's also the way to go if your PDF is a scan.

Print the page with your SSN.
Cover the number with a thick black marker. Go over it twice.
Hold the page up to a light. If you can still see any digits, cover them again.
Scan the page back into a PDF.

The scan is a picture, so the number is not in the file. The downside: it's slow and the page looks less sharp.

Way 3: A redact tool in PDF software

Some PDF programs have a real Redact tool, like Adobe Acrobat Pro. Some newer versions of Preview on a Mac also have a Redact option in the Tools menu. Use the redact tool, not the shape, pen or highlight tools. In programs that ask you to apply the redaction, do that before you save. Until then, the number is still there.

The 3-step safety test (do this every time)

Open the new file, not the original, and check:

Search. Press Ctrl + F (Windows) or Command + F (Mac). Type the last four digits of your SSN. It should find nothing.
Copy. Drag across the black bar, copy, and paste into Notepad (Windows) or TextEdit (Mac). No digits should appear.
Every page. Scroll through the whole file. Your SSN can show up more than once, for example in a page header.

If any check fails, don't send the file. Black it out again with a real redact tool.

Tips

Keep the original. Save the safe copy with a new name, like "W-9 - SSN hidden."
Check the file name. Don't put your SSN or full name in the file name.
Only send what they need. Pull out just the pages they asked for with PageKit before you black things out.
Number written a different way? If your form shows the number with spaces instead of dashes, and TrueRedact misses it, type it exactly as it appears in the box in step 3.

Frequently asked questions

Can I just draw a black box over my SSN?

Not safely. In most apps a box sits on top of the words, and the number is still in the file. Anyone can copy it out. You need a tool that takes the words out.

Does TrueRedact find my SSN by itself?

Yes. It already looks for Social Security numbers, bank account and card numbers, emails and phone numbers. Names are not found on their own, so type each name you want hidden.

Does TrueRedact upload my file?

No. Your PDF is opened and changed inside your web browser. It never leaves your device.

My PDF is a scan. What do I do?

TrueRedact can't read words inside a scan or photo. Use the print, marker and scan way in this guide instead.