Online Tool Store
Transparent PNG Maker
Make a background transparent by colour, with soft edges and halo removal, then download or copy the PNG. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Result
Click anywhere on the image to key that colour instead. The chequerboard is transparency, not part of the image.
How far from that colour still counts as background.
A band just past the tolerance that fades out instead of cutting.
PNG only, and for good reason. JPEG has no alpha channel, so saving this as a JPEG would fill every transparent pixel with black. Keying also has limits: it works cleanly on a flat, even background and struggles with gradients, shadows, and anything the same colour as the background — hair against white is the classic hard case.
How to use it
- Drop in an image — the background colour is guessed from the corners.
- If the guess is wrong, click the colour you want gone directly on the image.
- Raise the tolerance until the background clears, then stop.
- Download the PNG, or copy it straight to your clipboard. The chequerboard is transparency, not part of the file.
Why the distance is not plain RGB
Deciding whether a pixel counts as background means measuring how far its colour is from the key colour, and the obvious measure — straight-line distance in RGB — does not match how eyes work. It treats all three channels as equally important, so it scores red against green and red against blue as exactly the same amount of difference:
plain RGB redmean
red vs green 360.6 650
red vs blue 360.6 570
This tool uses the redmean weighting instead, which gives green four times the weight of the others and shifts the red and blue weights depending on how bright the pair being compared is. The practical effect is that one tolerance setting behaves consistently across different background colours, rather than being too aggressive on greens and too timid on blues. Its maximum — black against white — is 764.83, and the tolerance slider is a percentage of that.
The halo, and how to actually remove it
This is the part that separates a usable cut-out from an obvious one. Anywhere the subject has a curved or diagonal edge, the renderer blended subject and background together to smooth it. Those pixels are genuinely part background:
what you see colour = α × subject + (1 − α) × background
naive fix delete pure background → hard, jagged edge
soft key fade alpha across a band → smooth, but pale rim
un-blended subject = (colour − background × (1 − α)) / α → clean
So the edge band gets partial alpha and has the background colour algebraically removed from what remains. Without that second step a white background leaves a white fringe that shows up the moment you place the cut-out on anything dark. Untick "un-blend the edges" on the sample and the rim appears.
"Only the outside", and why it needs a flood fill
Keying by colour alone cannot tell a white backdrop from a white shirt — they are the same pixels. The fix is connectivity: start at the edges of the image and spread inwards through matching pixels only, so background enclosed by the subject is never reached. The fill is written iteratively with an explicit stack rather than recursively, because a recursive version on a 4,000-pixel-wide image runs out of call stack, and the colour distances are computed once up front instead of every time a pixel is visited.
What this approach cannot do
Colour keying needs a background that is reasonably flat and reasonably distinct from the subject. Gradients, shadows falling across the backdrop, motion blur, glass, smoke and fine hair all defeat it, because in those cases the right answer depends on context rather than on colour distance. That is the job of a trained matting model — a genuinely different technique, and a much heavier one. For a product shot on a white sweep or a logo on a solid field, this is faster and nothing leaves your machine.
FAQ
What is the pale outline left around my subject?
Background bleeding into the anti-aliased edge. Along any curve, the edge pixels are a mixture of subject and background, so deleting only the pure background leaves a rim of half-background colour. Un-blending fixes it properly: for each part-transparent pixel it solves the blend equation for the subject colour and puts that back.
Why did part of my subject disappear?
Because it was close enough in colour to the background. A white shirt against a white backdrop is the same pixels either way, and no amount of tolerance tuning separates them. Tick "only the outside" — it keeps only background that is connected to the edge of the image, so an interior white area survives.
What should I set the tolerance to?
As low as you can get away with. Start low and raise it until the background goes, then stop — every extra point also eats into edges and into anything similar in the subject. The percentage is a share of the largest possible colour difference, so 12% is a modest allowance rather than a twelfth of the palette.
Can it cut out hair, fur or glass?
Not well, and no colour-key tool can. Those need per-pixel transparency estimated from context rather than a distance threshold, which is what trained matting models do. If your subject has fine hair against a busy background, this is the wrong approach — a flat studio backdrop is what it is good at.
Can I save the result as a JPEG?
No, and you should not want to. JPEG has no alpha channel at all, so every transparent pixel would be filled in — black, usually. PNG is the format that carries transparency, which is why it is the only download offered.
Is my image uploaded anywhere?
No. It is decoded and processed in the page, and the download is generated in the browser. Nothing is sent to a server — which for anything containing a product shot, a signature or a document is the point.
Can I copy the result instead of downloading it?
Yes — Copy image puts the transparent PNG straight on your clipboard, ready to paste into a document, slide or chat without a round trip through your downloads folder. It uses the browser's clipboard image API, which needs a reasonably modern browser; if it is not available the button says so instead of silently failing.
How we compare
| Feature | Online Tool Store | AI background removers | Photoshop or GIMP |
|---|---|---|---|
| Image never leaves your device | ✓ | ✗ | ✓ |
| No signup, no credits, no watermark | ✓ | Usually limited or paid | Paid software |
| Un-blends edges instead of leaving a fringe | ✓ | Model dependent | ✓ |
| You control the exact threshold | ✓ | ✗ | ✓ |
| Instant, no queue or upload wait | ✓ | ✗ | ✓ |
| Copy the result straight to your clipboard | ✓ | Download only, on most | ✓ |
| Works on a busy or gradient background | ✗ | ✓ | ✓ |
| Cuts out hair, fur and glass | ✗ | ✓ | ✓ |
For a logo, a screenshot or a product shot on a flat backdrop this is the quickest honest route: instant, free, no upload, and you set the threshold yourself. It is genuinely worse than an AI remover on a complicated background, and the last two rows are where you should reach for one instead.