Background Colour Remover
ImagesEverything runs locally in your browser — nothing is uploaded
Drop an image here, or click to choose
Or press Ctrl/⌘ + V to paste a screenshot
PNG / JPEG / WebP / GIF / BMP / AVIF · up to 30 MB each
Pick a colour (the top-left pixel by default) and turn it into transparency, giving you a transparent PNG. The test is RGB Euclidean distance, not “equals this colour”. An exact comparison picks up almost nothing on a real photo: after JPEG compression the pixels inside one flat colour wobble by about ±3. So matching goes by three-channel distance, and the 0–100 tolerance in the UI maps linearly onto 0 to `sqrt(3 x 255^2)` (about 441.7). “Only the area connected to the edges” is how background removal should work. A whole-image scan also removes same-coloured parts inside the subject (a white shirt, a white hat against a white wall). Flooding with a 4-neighbour walk from the four edges eats only the region touching the border, so a same-coloured area enclosed by the subject is left alone. Edge feathering and de-fringing deal with hard edges: a binary cut has jaggies, so feathering ramps alpha by distance from the removed area, and de-fringing solves the target colour back out of soft pixels with `F = (C - (1-a) T) / a`. Without it, cutting a blue background leaves a blue halo around the subject. Everything runs locally.
Features
- Target colour from the top-left pixel by default, or set any colour by hand
- Matching by RGB distance, so JPEG wobble of ±3 is still caught where an exact match is not
- Connected-area mode floods 4-neighbour from the edges, sparing same-coloured areas inside the subject
- Tolerance from 0 to 100, biased towards being conservative
- Edge feathering from 0 to 5 pixels to soften the binary cut
- De-fringing solves the target colour out of soft edges, so no halo remains
- Exports a transparent PNG and reports what share of pixels was removed
- Nothing is uploaded; it works offline
How to use
- Drop an image in
- Choose where the target colour comes from, or set it by hand, and adjust the tolerance
- Turn on connected-area-only for backgrounds, then tune feathering and de-fringing
- The result appears at once; click Download for the transparent PNG
FAQ
- Why is a distance used instead of an exact colour match?
- Because photos are lossily compressed: inside one flat area of a JPEG the pixels differ by about ±3. Comparing for an exact match hits so few pixels that almost nothing is removed. Three-channel Euclidean distance fixes that, with the 0–100 tolerance mapping onto 0 to about 441.7. The default 20 already removes most backgrounds without eating into the subject.
- What does connected-area-only actually do?
- It decides which pixels go. When on, a 4-neighbour flood starts from the four edges and removes only what touches the border and falls within tolerance, so a white shirt enclosed by a face and shoulders is untouched. When off it scans the whole image, removing every pixel close to the target colour, including same-coloured parts inside the subject. Keep it on for background removal.
- What are feathering and de-fringing for?
- A binary cut has hard, jagged edges that show a rim of the old background on light surfaces. Feathering ramps the edge alpha by distance from the removed area; de-fringing solves the leftover target colour out of soft pixels, so cutting a blue background leaves no blue halo. Turn both off when the subject edge is already clean.
- Is the image uploaded?
- No. The cut-out is done in your browser with canvas, entirely in local memory, and it works offline.
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