Reduce image noise
Reduce noise in a photo or scan (specks, dust, stuck pixels and grain) free and in your browser with no upload. A median filter removes specks outright, and an edge-preserving filter smooths grain without blurring edges.
A median filter: each pixel becomes the middle value of its neighbors. It removes specks without smearing edges the way a blur does.
In detail
Denoise removes speckle and sensor noise with two filters. A median replaces each pixel with the middle value of its neighbors, which removes a stuck pixel completely, since a single speck is never the middle of anything, while a straight edge survives. An edge-preserving average only averages neighbors whose color is already close to the center pixel, so grain in flat areas smooths out and edges stay put.
The preview runs at 1:1, because a shrunken preview averages the speckle away and makes every setting look clean. Neither filter can put back the detail the noise was sitting on, so keep the radius as small as does the job.
Reduce image noise at a glance
- Input
- JPG, PNG, WebP, AVIF, HEIC, GIF (first frame), BMP, TIFF, SVG and other image formats
- Output
- The original format, PNG, WebP or JPEG
- What it does
- A median filter for specks and dust
- An edge-preserving filter for grain
- Radius from 1 to 5
- Color threshold control
- A 1:1 preview and full-resolution export
- Batch processing
- Who it is for
- Anyone with a grainy low-light photo or a dusty, speckled scan.
- Limits
- Large radii soften fine texture and small text.
- Big radii on very large photos take a few seconds per file.
- Privacy
- Runs entirely in your browser: no file is uploaded, and nothing is kept after you close the tab.
How to reduce noise in an image
- Drop your images Drag one or more images in. They are decoded and the preview opens at full size.
- Pick a method Median removes specks, dust and stuck pixels. Edge-preserving smooths grain across flat areas by averaging only neighbors of a similar color.
- Set the radius Radius 1 is a 3-by-3 window and it goes up to 5, an 11-by-11 window. Every step up removes larger clumps and takes more fine texture with it.
- Set the color threshold This appears for the edge-preserving filter only: how different a neighbor may be, in levels out of 255, and still be averaged in. Below it is noise, above it is an edge. The default is 28; at zero almost nothing changes.
- Check at 1:1, then apply Drag or arrow-key around the preview before running the batch, then apply and take one file or a ZIP.
Reduce image noise: common questions
Median or edge-preserving — which should I use?
Use the median for discrete specks: dust on a scan, hot pixels, salt-and-pepper noise, since a single stray value is never the middle of its neighborhood and disappears outright. Use edge-preserving for even grain across flat areas, since it averages only neighbors already close in color, so grain inside that window averages away while the far side of an edge is never counted.
What can denoising not do?
Neither filter can put back the detail the noise was sitting on top of. From a radius of 3 upward both start eating small text, fur and film grain along with the noise, which is exactly why the preview runs at one image pixel per screen pixel rather than as a fitted thumbnail.
Is it slow on large photographs?
It can be. Both filters read a window of source pixels around every pixel they write, and a 7-by-7 window over an 8-megapixel photo takes a few seconds a file. The median uses a sliding histogram, so its cost grows with the radius rather than with the square of it. The export always runs at full resolution however small the preview window is.