Before you share a photo, you might need to protect someone’s identity — a bystander in the background, a child at a school event, or even yourself in an image that’s going somewhere public. Blurring or pixelating a face is the fastest way to do that, and you shouldn’t need to install software, create an account, or upload your photo to a stranger’s server to get it done.

This guide walks you through exactly how to blur or pixelate a face in a photo using BlurPen — a free, browser-based redaction tool where your file never leaves your device.

Why face blurring matters

Privacy and consent are increasingly important considerations whenever photos are shared online. Specific situations where you’ll want to blur faces include:

Sharing a group photo publicly when not everyone has consented to appearing online
Posting candid street photography where individuals are identifiable
Complying with GDPR or similar data protection laws when publishing images that contain people’s faces
Protecting a source or witness in documentary or journalism work
Publishing security footage for awareness without exposing the individuals involved

Beyond privacy, face blurring is simply good practice. Once a photo is online, you lose control of where it ends up — blurring upfront is far easier than trying to take it down later.

Blur vs. pixelate: which should you use for faces?

BlurPen gives you two effect options: Gaussian blur and pixelation. For faces, pixelation (also called a mosaic effect) is the safer choice for two reasons:

It discards information. Pixelation replaces the face with a grid of solid-colour blocks. The original pixel data is gone — there’s no way to “un-pixelate” it. Gaussian blur, by contrast, is a mathematical transformation of the existing pixel data. With enough processing power and the right algorithms, a blurred face can theoretically be partially reconstructed.
It reads as “deliberately redacted.” A pixelated face signals intentional privacy protection, which is important in professional or legal contexts. A blurred face can sometimes look accidental.

For light use — hiding a face in a casual social media post — Gaussian blur at High or Max intensity is fine. For anything sensitive, use pixelation at High or Max intensity.

Step-by-step: how to blur a face with BlurPen

Step 1: Open BlurPen

Navigate to blurpen.com. No download, no extension, no sign-up. The tool runs entirely in your browser — Chrome, Firefox, Safari 16+, or Edge all work.

Step 2: Upload your image

Drag your photo onto the upload zone or click to browse. BlurPen accepts PNG, JPG, WebP, and GIF files up to 50 MB. Your file is loaded directly into your browser’s memory — it is never sent to any server.

Step 3: Select the Ellipse tool

In the toolbar, click the ⬭ Ellipse button or press E. The ellipse tool is the best choice for faces because faces are roughly oval. It lets you draw an ellipse around the face and applies the blur effect precisely within that shape — pixels outside the ellipse (like the hair or neck) are untouched.

If you’re working with a group photo with multiple faces, you’ll repeat this process for each one.

Step 4: Set your effect and intensity

In the toolbar, make sure Pixelation is selected in the effect toggle (or press G to cycle between Gaussian and Pixelation). Set the intensity slider to High or Max for faces.

Step 5: Draw over the face

Click and drag to draw an ellipse around the face. Hold Shift while dragging to constrain the ellipse to a perfect circle — useful for head-on portrait shots. When you release, the pixelation effect is applied immediately within the ellipse boundary.

Use Ctrl+Z (or Cmd+Z on Mac) to undo and redraw if you missed the face or want to adjust.

Tip: Press + to zoom in before drawing if the face is small in the frame. This makes it much easier to draw an accurate ellipse around just the face without accidentally covering surrounding detail.

Step 6: Repeat for additional faces

Navigate the image using the zoom controls and repeat for each face that needs to be redacted. Each stroke is independent — undoing one doesn’t affect the others.

Step 7: Export and download

Click ⬇ Save in the toolbar and choose Save as PNG for lossless quality, or Save as JPG for a smaller file. Your redacted image downloads directly to your device with a _blurred suffix added to the filename.

Common mistakes to avoid

Blurring too little. A light Gaussian blur at Low intensity on a large, well-lit face may not be enough to prevent identification. Use High or Max intensity, especially for close-up portraits.

Using Gaussian blur for sensitive content. As described above, Gaussian blur is reversible in theory. For any legal, journalistic, or compliance use case, use pixelation.

Forgetting the ears and hairline. Faces are sometimes identifiable by ear shape, distinctive hair, or other features near the face. Consider whether the ellipse is large enough to cover these too.

Exporting as JPG at low quality. JPG compression can introduce artefacts around the edges of your pixelated area that partially reveal the underlying pixels. Export as PNG for pixel-perfect results.

What about PDFs?

If the face appears inside a PDF — for example, a scanned ID, a document with a photo, or a court filing — BlurPen handles that too. It’s the only free browser tool that lets you redact PDFs as well as images. Learn how to redact a PDF online →

Privacy note

BlurPen processes everything in your browser. The pixel data of your photo is never transmitted anywhere. You can verify this by opening your browser’s DevTools Network tab while using BlurPen — you’ll see zero file-upload requests.

Also worth knowing: BlurPen is ad-supported, which means third-party ad scripts run on the page. Those scripts have no access to your canvas or file data — that’s a browser security boundary. But we disclose it so you can make an informed decision. Your file is private; standard ad-network browsing signals are not. Our Privacy Policy has the full breakdown.