About this tool
Image blur softens detail. The most common use today is privacy redaction - blurring faces, license plates, addresses, or screen contents before sharing. The other big use is creative: shallow depth-of-field background blur, motion-blur effects, and softening backgrounds behind text overlays.
This tool applies a Gaussian blur using the browser CSS filter pipeline. Blur strength is in pixels (the standard deviation of the Gaussian kernel). Strength 2-4 is enough to render small text unreadable; 8-16 obscures faces; 25+ creates abstract backgrounds. For privacy redaction we recommend at least 12px on the area you want to obscure.
How it works
Open the image
Drop or pick a JPG, PNG, WebP, or GIF.
Set the blur strength
Drag the slider from 1 (barely visible) to 50 (heavy). Most privacy redactions land at 15-25.
Apply to whole image or a selection
For a full-image effect, just adjust the slider. For face/license-plate redaction, select the area and apply blur only inside it.
Download
The blurred result saves to your device. PNG keeps transparency; JPG re-encodes.
Use cases
Privacy redaction
Before sharing screenshots that contain personal data, blur emails, account numbers, addresses. Blur should be aggressive enough that no detail can be reconstructed - 15+ pixels.
Face anonymization
Group photos shared publicly often need bystander faces blurred for consent. Use selection-blur to isolate faces.
Background softening
Behind a text-heavy quote graphic or a CTA, a blurred photo background gives focus to the foreground text without distracting detail.
Frosted-glass UI mockups
Light blur (3-6 px) under a translucent overlay simulates the macOS / iOS frosted-glass look.
Hide spoilers
Blogging about TV shows or games? Light-medium blur on screenshot until the user clicks to reveal.
Format and spec details
| Blur algorithm | Gaussian blur via CSS filter and Canvas re-render |
|---|---|
| Strength range | 1-50 px standard deviation |
| Privacy threshold | 12+ px for faces, 8+ px for small text |
| Reversible? | No - blur is destructive. The detail is gone. Even AI deblurring cannot recover specific pixels. |
Tips and best practices
- For privacy: 12+ px on faces, 15+ px on text. Bigger is safer.
- Apply blur as the last step - subsequent crops or resizes can sharpen edges and partially undo the privacy effect.
- Save as PNG to keep the blur lossless; saving as JPG re-encodes and adds compression artifacts on top of the blur.
- Background blur for text overlays: try 5-10 px with a 60% opacity dark overlay on top.
How to use the Image Blur
The Image Blur is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Image Blur-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
Privacy and offline operation
Every operation in this tool runs client-side using your browser's built-in APIs (Canvas, Web Audio, WebAssembly). No data is uploaded. After the initial page load you can disconnect from the internet and the tool keeps working.
We use Google Analytics and AdSense for the page itself, but neither sees the content of the files you process.
Frequently asked questions
Can blur be reversed?
Not meaningfully. Heavy Gaussian blur is mathematically lossy - the original pixels are not recoverable. Some shallow blurs can be partially reversed by AI deconvolution, which is why we recommend 15+ px for sensitive redaction.
Is pixelation safer than blur for privacy?
Both are destructive at high strength. Pixelation can be more vulnerable to resolution-based attacks (fewer unique tiles); strong Gaussian blur (20+ px) is harder to reverse.
Does blur change file size?
Slightly. A blurred JPG often compresses smaller because high-frequency detail is gone. PNG sizes change less.
Will blur affect transparency?
PNG and WebP transparency is preserved. JPG has no transparency; transparent areas become white.
Can I selectively blur just a face?
Yes - the tool supports a rectangular selection. For non-rectangular shapes (an ear, a tattoo), use a layered editor.
Is the Image Blur accurate?
The Image Blur applies the standard formula for image blur. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Image Blur free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
Can I use the Image Blur on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum guidance.
How do I report a bug or suggest improvement to the Image Blur?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours and update calculators when rules or formulas change.
How accurate is the Image Blur?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Image Blur free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Does the Image Blur work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
Can I share results from the Image Blur?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another image blur tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.