Check whether a PNG image contains transparency
Analyze an image's alpha channel and get the exact percentage of fully transparent, semi-transparent and fully opaque pixels — useful for checking an export before you use it.
How it works
The tool scans the alpha channel (the fourth channel, after red, green and blue) of every pixel in the image and sorts each one into one of three categories: fully transparent (alpha = 0, invisible), semi-transparent (alpha between 1 and 254, partially visible), or fully opaque (alpha = 255, no transparency). The result shows the number and percentage of pixels in each category.
Why does a JPEG image always show 100% opaque pixels?
The JPEG format doesn't support transparency at all, so all of its pixels are necessarily treated as fully opaque (alpha = 255), whatever they look like. Only formats such as PNG, WebP or GIF can actually contain transparent or semi-transparent areas.
Why does the percentage of semi-transparent pixels matter?
A high percentage of semi-transparent pixels often indicates anti-aliased (soft) edges around a cut-out subject, which is normal and gives a cleaner look. A very low percentage with many fully transparent or fully opaque pixels may indicate a "harder" cut-out, with no smooth transition at the edges.
100% local processing: the alpha channel analysis happens entirely in your browser — your image is never sent to a server.