Image Blur: Blur Part of an Image with Pixelate or Gaussian Blur
You just took a screenshot to share with a colleague, but there is an email address, an account balance, or a face in the frame that should not be public. Cropping cuts out the wrong context, and a black rectangle screams "something was hidden here." A blur is the cleaner answer: it obscures the sensitive region while keeping the rest of the image intact and natural. Our free Image Blur tool lets you brush over any part of a photo or screenshot and apply a Gaussian blur or a pixelate effect right in your browser.
Gaussian Blur vs. Pixelate: What Is the Difference?
Both effects hide detail, but they do it differently. A Gaussian blur averages each pixel with its neighbours using a bell-curve weighting, producing a soft, smeared look β the same effect a camera creates when a subject is out of focus. Pixelate (also called mosaic) divides the region into a grid of large blocks and fills each block with the average colour of the pixels underneath, giving the classic censored-TV look. Choose based on the message you want to send:
- β’ Gaussian blur β best for a subtle, organic effect on backgrounds, faces, or license plates where you want the redaction to blend in.
- β’ Pixelate β best when you want it obvious that information was deliberately hidden, such as redacting an ID number in documentation.
One important note on security: a light blur is reversible. Researchers have reconstructed pixelated text and lightly blurred faces using machine learning. For anything truly confidential β passwords, government IDs, credit card numbers β use a strong blur radius or large pixel blocks, or overlay a solid shape instead.
How to Blur Part of an Image
- 1.Upload your image or drag and drop it onto the tool β JPG, PNG, and WebP are all supported.
- 2.Pick your effect: Gaussian blur for a soft smear, or Pixelate for a block mosaic.
- 3.Set the strength β a higher blur radius or larger pixel size hides more detail.
- 4.Draw a selection over each area you want to obscure. You can add several regions to one image.
- 5.Preview the result, adjust if needed, then download the edited image with one click.
Who Needs This β Real Use Cases
Blurring part of an image is one of those small tasks that comes up constantly once you start noticing it. A few common examples:
- β’ Support and bug reports β hide API keys, tokens, and internal URLs before pasting a screenshot into a ticket or chat.
- β’ Selling online β blur your home address on a delivery label or your face in a mirror when photographing an item for a marketplace.
- β’ Content creators β obscure bystanders' faces, license plates, or house numbers in vlogs and blog photos to respect privacy.
- β’ Teachers and writers β redact student names or personal data in an example document shared with a class.
A Concrete Example
Say you are documenting a settings page and the top-right corner shows your account email. Choose Pixelate, set the block size to roughly 20 pixels, and draw a box around the email field:
At 20-pixel blocks, a 32-pixel-tall line of text is reduced to fewer than two rows of colour squares β far too coarse for the original characters to be recovered. Bump the block size to 40 for an even safer margin on small sensitive fields.
Everything Happens in Your Browser
The whole point of blurring an image is usually privacy β so it would be counterproductive to upload that image to a stranger's server first. This tool processes your file entirely on your own device using the HTML5 Canvas API. Nothing is transmitted over the internet, nothing is stored, and no account is required. That also means it works offline and stays fast even on a phone with a weak connection. When you download the result, only the pixels you chose to keep leave your machine.
Try it now β 100% free, no sign-up required
Open Image Blur βFrequently Asked Questions
Can a blurred image be un-blurred?
Sometimes. A weak Gaussian blur or a coarse pixelation applied to predictable content like printed text can be partially reversed by specialised software, because the effect still leaves statistical traces of the original. For genuinely secret information, use a heavy blur radius or large pixel blocks so no meaningful detail survives β or overlay a solid black shape, which removes the underlying data entirely rather than just scrambling it.
Does blurring change the whole image or just the selected area?
Only the regions you draw are affected. The rest of the image is preserved at full quality, so you can hide a single face or an address without softening the entire photo. You can add multiple regions to one image if there is more than one thing to obscure.
What file formats can I use?
You can upload JPG, PNG, and WebP files. Screenshots are usually PNG, which is fine. If your export needs a transparent background, keep it as PNG; for photographs headed to social media, JPG produces a smaller file at the same visual quality.
Is it really free, and are there limits?
Yes β it is completely free with no watermark, no trial, and no account. Because everything runs locally in your browser, there are no upload size caps beyond what your own device can handle. If you find it useful, the full toolbox has more free image and text utilities, and the blog covers how to use each one.