How to Blur an Image
People come to a blur tool for two almost unrelated reasons. The first is aesthetic — softening a photograph so text can sit legibly on top of it — and for that the whole-image mode with a moderate strength is all you need. The second is redaction, and it deserves more care. If you're hiding a face, a number plate, an email address in a screenshot or a name on a document, you need the blur confined to that area and everything else left sharp, which is what the region mode does: drag the shape over what needs covering, resize it with the corner handle, and choose an oval for faces or a rectangle for lines of text. Two things are worth being direct about. A light blur is not reliable protection — enough structure can survive that determined recovery is sometimes possible — so for anything genuinely sensitive push the strength high, or use pixelation or a solid box instead. And the redaction must be flattened into a new image file. Covering something with a shape inside a document or presentation leaves the original underneath for anyone who opens the file properly; exporting a real image, as this tool does, removes that risk entirely. Everything is processed on your device, which matters more here than on almost any other tool.
Add your images
Drag and drop, paste, or click to browse — multiple at once.
Choose the mode
Whole image, or drag a region over what needs hiding.
Download
Save each image, or take the whole batch as one ZIP.
What a Blur Actually Does
Averaging neighbours
Each pixel is replaced by a weighted average of the pixels around it. A larger radius pulls in more neighbours, so fine detail disappears first and only broad shapes and colours remain.
Why strength matters for privacy
At low strength the original values are smeared rather than destroyed, and traces of the underlying pattern remain. At high strength the information is genuinely gone, which is the difference between obscuring something and actually removing it.
Common Use Cases
Hide a face
Blur a bystander before posting a photo publicly.
Redact a screenshot
Cover an email address, token or account number.
Number plates
Obscure a registration before sharing a vehicle photo.
Background for text
Soften a whole image so overlaid words stay readable.
Anonymise documents
Hide names and addresses in a photographed form.
Property listings
Blur a house number or neighbouring windows.
Bug reports
Share a screenshot without exposing customer data.
Depth effect
A light whole-image blur behind a sharp foreground element.
Tips & Best Practices
Go heavy for anything sensitive
A light blur is decoration, not protection. If it matters, push the strength high or use a solid box.
Cover more than you think
Extend the region past the edges of what you're hiding — partial detail at the boundary can give it away.
Use an oval for faces
It follows the shape of a head far better than a rectangle and looks less like an obvious censor bar.
Check the result at full size
Something that looks hidden in a small preview can still be legible when zoomed in.
Never rely on a shape in a document
Covering text in a PDF or slide leaves the original underneath. Export a flattened image instead.
Redact before compressing
Do the blur first so compression works on the final image rather than being undone by it.
Troubleshooting
I can still read the text
The strength is too low or the region too small. Increase both — for redaction the area should be completely featureless.
The region is in the wrong place on some images
The position is a percentage applied to every image, so it only lines up across a batch if the subject is in the same place.
The blur edge looks harsh
Switch to the oval shape, which reads as more natural than a hard rectangle.
The whole image got blurred
Whole-image mode is selected. Switch to region mode and position the shape.
Frequently Asked Questions
How do I blur an image for free?
Drop your images above, choose whole-image or region blur, set the strength and download — free, no signup and no watermark.
Can I blur just part of an image?
Yes. Switch to region mode and drag the shape over the area you want hidden — everything else stays sharp.
Are my images uploaded to a server?
No. Blurring happens entirely in your browser, which matters when you're redacting something sensitive.
Is blurring safe for hiding private information?
Only at high strength. A light blur can sometimes be partially reversed — for anything sensitive, use heavy blur, pixelation or a solid box.
Can a blur be reversed?
A light one sometimes can, because the underlying pattern is smeared rather than destroyed. Heavy blurring removes the information properly.
How do I blur a face?
Use region mode with the oval shape, cover the whole head generously, and set a high strength.
Can I blur several images at once?
Yes, though in region mode the same position applies to all of them — useful when the subject is in a consistent place.
What shape should I use?
Oval for faces, rectangle for text, number plates and screenshot lines.
Why not just cover it with a black box in a document?
Because the original data usually remains underneath and can be recovered. A flattened image file has no such layer.
How strong should the blur be?
For aesthetics, whatever looks right. For redaction, strong enough that no structure at all remains visible when zoomed in.
Is there a file size limit?
No. Nothing is uploaded, so the only constraint is your device's memory.
Which format should I choose?
JPEG for photos and a smaller file, PNG when you need lossless quality or transparency.
Can I undo the blur?
Not from the saved file — that's the point. Keep your original if you might need it.
Does it remove EXIF data?
Yes. Canvas-based processing drops metadata, including any GPS coordinates — worth knowing when sharing photos publicly.
Should I use blur or pixelation?
Both work at high strength. Pixelation looks more deliberate as a censor; heavy blur looks more natural.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so it keeps working without a connection.
Does it work on phones?
Yes, in any modern browser on Windows, Mac, Android or iPhone with nothing to install.
Is this tool really free?
Completely free, forever — no account, no ads and no premium wall.
100% free · No signup · Processed in your browser · Never uploaded
Last updated: September 2026 · FlipMyFormat Image Blur
Written and maintained by the FlipMyFormat team · Runs entirely in your browser