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Blur image online free

Add Gaussian-style blur to photos for backgrounds or privacy. Dial strength, preview, download PNG.

What is image blur?

Blur softens detail for backgrounds, frosted UI panels, or hiding faces in a pinch. This page applies a controllable blur strength and shows a live preview so you can stop before the image turns into fog.

Blur filter types

Seven blurring modes with type-specific controls.

  1. Stack blur: Fast stacked smoothing with radius control.

  2. Gaussian blur: Soft Gaussian-style falloff via multi-pass box blur.

  3. Motion blur: Directional streaks with kernel size and degrees.

  4. Box blur: Classic separable box average blur.

  5. Radial blur: Zoom blur from adjustable horizontal and vertical center.

  6. Heavy radial blur: Stronger radial streaks with the same center controls.

  7. Soften: 3×3 or 5×5 low-pass mean filter with strongness blend.

How to blur a photo

Steps for online picture blurring.

  1. Upload the image

    Drop or click in the input panel (15 MB max).

  2. Pick a filter type

    Select stack, Gaussian, motion, box, radial, heavy radial, or soften.

  3. Tune controls

    Radius, kernel, degrees, center, size, strongness, or mask size depending on type.

  4. Download PNG

    Save when the blurred preview matches your goal.

Tips for blurring images

Better blur results.
  • 01

    Start with low radius

    Increase radius gradually, heavy blur is hard to undo without the original.

  • 02

    Resize large photos first

    Downscale on /resize-image before extreme radius values for faster runs.

  • 03

    Motion blur angle

    Match degrees to the direction of movement in the scene.

  • 04

    Radial center

    Place the center on the subject for zoom-style emphasis.

  • 05

    Partial blur workaround

    Crop the area to blur on /crop-image, blur that file, then layer in your editor.

  • 06

    Compare filters

    Switch types on the same upload to pick the look you need.

Blur Image Tools Compared — Which One Fits Your Workflow

How this free blur image tool stacks up against other popular online options for blurring images.

  1. Adobe Express

    Quick online blur tool with adjustable slider. Part of Adobe's suite requires navigating away from the blur tool to access other editing features. Free plan includes core features but watermarked exports on some formats.

  2. Fotor.com

    AI-powered blur editor with automatic detection and brush refinement. Pro subscription required for AI features; free tier limited.

  3. ImageOnline.co

    Simple image-wide blur with single slider. No selective blur, no preview comparison panel exposed.

  4. PineTools.com

    Basic Gaussian blur with upload-apply-download flow. Requires clicking "Apply" instead of real-time preview.

  5. Blur Image

    One slider controls blur radius (1-50) with box blur algorithm. Real-time preview updates as you drag. Side-by-side original vs blurred comparison. All processing in browser.

When to blur images

Typical uses for blur filters.

  • Soft photo backgrounds

    Gaussian or stack blur for overall background softening—not selective masking.

  • Motion effects

    Motion blur for speed lines and action shots.

  • Privacy before sharing

    Blur a whole crop that contains sensitive details before posting.

  • Depth cues

    Radial blur for zoom or spin emphasis from a chosen center.

  • UI mockups

    Soften or Gaussian blur on hero images behind modal concepts.

  • Light noise smoothing

    Gentle soften or box blur on mildly noisy photos.

Why use this blur tool

Benefits of browser-based blurring.

  • Seven filter modes

    Gaussian, motion, stack, and more on one page.

  • Live preview

    Output updates as you change type and sliders.

  • Private

    Images stay on your device, no server upload.

  • Type-specific controls

    Only relevant sliders show for each filter.

  • PNG export

    Download blurred PNG with alpha when the upload had transparency.

  • Free

    Unlimited previews and PNG downloads.

Technical details

How blur processing works here.
Separable box blur
Horizontal and vertical passes for box, stack, and Gaussian modes.
Gaussian approximation
Three box passes with weighted radii approximate Gaussian falloff.
Motion sampling
Averages pixels along a line at the chosen angle and kernel length.
Radial sampling
Zoom-blur samples from center toward each pixel; heavy mode uses more steps.
Soften mean filter
3×3 or 5×5 neighborhood average blended by strongness.
Input limits
15 MB upload; 8192 px max edge; radius and kernel capped at 100.

Sources & References

Authoritative references on Gaussian blur, convolution-based image smoothing, and the Canvas rendering technology this tool uses.
  • “Gaussian blur is a type of image-blurring filter that uses a Gaussian function to calculate the transformation.”
    — Wikipedia — Gaussian blur

    Gaussian blur in image processing: Gaussian blur applies a weighted average determined by the Gaussian bell curve, producing a smooth, natural-looking blur. This tool approximates Gaussian blur with multi-pass box blur. en.wikipedia.org/wiki/Gaussian_blur

  • “The Canvas API provides a means for drawing graphics via JavaScript and the HTML canvas element.”
    — MDN Web Docs — Canvas API

    Canvas API (client-side pixel manipulation): All blur filters in this tool — Gaussian, motion, box, radial, stack, and soften — run on Canvas 2D pixel buffers using separable convolution passes, processed entirely in your browser. developer.mozilla.org/en-US/docs/Web/API/Canvas_API

  • “PNG supports lossless data compression, making it useful for storing graphics that need to be edited repeatedly without losing quality.”
    — W3C — PNG Specification (overview)

    PNG image format: Downloading a blurred image as PNG preserves the smooth gradients created by blur filters without compression artifacts. w3.org/TR/PNG/

  • “Depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.”
    — Wikipedia — Depth of field

    Depth of field in photography: Blur effects simulate shallow depth of field. Understanding depth of field helps photographers choose the right blur strength for creative or corrective purposes. en.wikipedia.org/wiki/Depth_of_field

Frequently Asked Questions

Quick answers about this tool—open a question to read more.