Background Remover & Replacer
Remove a green screen, blue screen or plain white backdrop and save a transparent PNG, or put the subject on a new colour, gradient or picture. It keys by colour, so it works when the background is one distinct colour.
How to Use
- Choose a mode: Chroma key for a green or blue screen, Colour to transparent for a white or other plain backdrop, or Replace background to put the subject on something new. A sample is keyed straight away so you can see each control work.
- Drop your own image on the drop box (or paste it). The key colour is read from the image border automatically; click the preview to pick a different one with the eyedropper.
- Raise Tolerance until the backdrop disappears, then use Softness for smooth edges. The histogram in Show Work shows where the backdrop and the subject sit, so you can put the line in the gap.
- For a green or blue screen, turn up Spill suppression to remove the coloured fringe on hair and shoulders. Leave Connected to edges only on for product shots so a white label inside the subject is not cut out.
- Check the result with Before / after and Mask, on a checkerboard, white or black backing.
- Save it with the export panel: PNG or WebP keep the transparency; JPG is flattened onto the colour you choose. In Replace mode the result is opaque and saves to any format.
Worked Example
A green screen. Key #00B140 = rgb(0, 177, 64), tolerance 12% and softness 10%. The largest RGB distance is √(3 × 255²) = 441.67, so everything within 0.12 × 441.67 = 53.0 is removed and the fade runs from 53.0 to 97.2.
A shadowed corner of the screen, rgb(0, 150, 52): d = √(0² + 27² + 12²) = 29.5, inside 53.0, so it becomes fully transparent. A cheek, rgb(227, 169, 130): d = √(227² + 8² + 66²) = 236.5, far outside, so it is kept. A hair-edge pixel that is half hair and half screen, rgb(22, 103, 43): d = 80.0, inside the fade, so alpha = 255 × (80.0 − 53.0) ÷ 44.2 = 156 (61% opaque). Taking the key back out, C′ = (C − 0.39 × K) ÷ 0.61, gives rgb(36, 56, 30), and 70% spill suppression brings green down to 42: rgb(36, 42, 30), a dark brown instead of a green fringe.
A product on white. Key #FFFFFF, tolerance 6% (26.5) and softness 10% (fade to 70.7). The off-white floor, rgb(247, 247, 247), is 13.9 away and disappears. A pale shadow, rgb(230, 230, 230), is 43.3 away: alpha 97 (38%), and its cleaned colour is rgb(189, 189, 189), so the shadow survives as a soft grey shade. The white label, rgb(254, 254, 254), is only 1.7 away, but with Connected to edges only on it is enclosed by the bottle and stays.
The common mistake: pushing tolerance up until the last speck of screen is gone. At 50% the cut-off is 220.8 and the fade reaches 265.0, so the cheek at 236.5 is no longer safe: it comes out at alpha 91, only 36% opaque, and the face turns see-through. Fix the lighting or pick the key from the darkest part of the screen instead; keep tolerance just above the backdrop’s spread (12% here) and let softness and spill suppression handle the edges.
Show Work
How It Works
From Blue Screens to Alpha Channels
Film-makers were combining separately shot elements long before computers. The Thief of Bagdad (1940), whose effects team led by Larry Butler won the Academy Award for special effects, used an early colour-separation blue-screen process. In the late 1950s Petro Vlahos developed the colour-difference blue-screen method used on Ben-Hur (1959), and the Academy later honoured him for his compositing work.
The idea of storing transparency as a channel of its own came from computer graphics. Alvy Ray Smith and Ed Catmull introduced the integral alpha channel in the 1970s, and in 1984 Thomas Porter and Tom Duff published “Compositing Digital Images”, which defined the “over” operation this tool uses in Replace mode. PNG, standardised in 1996, made 8-bit alpha an everyday file feature.
Green largely replaced blue for video because digital camera sensors have twice as many green photosites as red or blue in the usual Bayer pattern, so the green channel is the cleanest, and green is far from skin tones. Blue is still the choice when the subject wears green.
About This Tool
This tool replaces three separate pages: the chroma key, the transparent-PNG maker and the background replacer. They all do the same job: decide how far each pixel is from one background colour, turn that into an alpha value, and either save it or put a new background behind it.
It is honest colour keying, not AI subject detection. It works when the background is one distinct colour that the subject does not contain: a lit green or blue screen, a white sweep, a plain wall, a scanned page. It reads the 205 image formats the site’s image engine can decode, and everything runs in your browser; your pictures are never uploaded.
It suits video makers with a green screen, online sellers with white-background product photos, and anyone tidying a logo or a signature for a document.
Related tools: Color Replace, Universal Image Converter, and Image Resizer.
Frequently Asked Questions
Is this an AI background remover?
No. It keys by colour: every pixel close enough to the key colour becomes transparent. That is exactly right for a green screen, a blue screen or a studio shot on seamless white, and it never invents edges. It cannot separate a person from a busy street or a patterned sofa; for those you need a tool that recognises the subject.
What tolerance should I use?
Start low and raise it until the backdrop is gone. On an evenly lit green screen 8–15% is typical; a white sweep usually needs only 4–8%. Tolerance is a share of the largest possible colour distance (441.67 in RGB), so 12% removes everything within 53.0 of the key. Too high and the subject starts to fade: at 50% a skin tone 236.5 away from #00B140 keeps only 36% of its opacity.
What is spill, and what does spill suppression do?
Light bouncing off a green screen tints the edges of hair, shoulders and anything shiny green. Spill suppression pulls the key’s strongest channel down towards the other two: G′ = G − s × (G − max(R, B)). At 70% an edge pixel of rgb(36, 56, 30) becomes rgb(36, 42, 30), close to the dark brown hair it really is. Skin and yellows are untouched because their green is not the largest channel.
Why does my white logo lose the inside of its letters?
White inside an O or an A is the same colour as the backdrop, so a global key removes it too. Turn on Connected to edges only: the tool then floods in from the image border and removes only background it can reach, so enclosed white (letter counters, a white label on a bottle) stays. Turn it off when you do want those holes cut out.
Can I save a JPG with a transparent background?
No format change can do that: JPG has no alpha channel. Saving as JPG flattens the result onto the colour in JPG background (white by default). Use PNG for the widest support, WebP for smaller files, or AVIF; all keep full 8-bit transparency. Nothing is uploaded; the keying and the encoding run in your browser.
How do I use the Background Remover & Replacer?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Green-screen stills
Key a frame shot on #00B140 at 12% tolerance and 70% spill suppression, then drop it onto a slide or a thumbnail.
Product photos on white
Turn a white-sweep packshot transparent at 6% tolerance with Connected to edges on, so the white label survives.
Logos and signatures
Scan a signature on white paper and key it at 10–20% softness for smooth, fringe-free strokes on any document.
New backdrops
Swap a plain studio wall for a navy-to-sky gradient or your own photo; the background is scaled to cover the whole frame.
Game and app sprites
Key character art drawn on a magenta #FF00FF background with 0% softness for hard pixel-art edges.
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