BYTETOOLS

Alpha Channel Extractor

Extract the alpha channel of a PNG as a grayscale mask, see how much of the image is transparent, and invert or threshold the matte before downloading.

Drop a PNG (or any image with transparency)Processed locally — never uploaded

What is the Alpha Channel Extractor?

Every pixel in a PNG carries an alpha byte that says how opaque it is. This tool reads that byte for the whole image and writes it out as a grayscale mask — white where the pixel is fully opaque, black where it is completely transparent, and grey for the soft antialiased edges in between.

  • Alpha channel exported as a plain grayscale PNG mask
  • Full-resolution counts of transparent, semi-transparent and opaque pixels
  • Reported minimum and maximum alpha values for the file
  • Invert option so white can mean transparent
  • Adjustable threshold that flattens the mask to a hard matte
  • 100% in-browser — the artwork is never uploaded

How to use the Alpha Channel Extractor

  1. 1

    Drop a PNG, WebP or GIF with transparency into the upload area.

  2. 2

    Read the transparency statistics to see how much of the image is opaque, semi-transparent or clear.

  3. 3

    Tick Invert mask if you need white to mean transparent instead of opaque.

  4. 4

    Tick Threshold to a hard matte and set the cut-off when soft edges are not wanted.

  5. 5

    Click Download PNG to save the mask shown beside the original.

About the Alpha Channel Extractor

Every pixel in a PNG carries an alpha byte that says how opaque it is. This tool reads that byte for the whole image and writes it out as a grayscale mask — white where the pixel is fully opaque, black where it is completely transparent, and grey for the soft antialiased edges in between.

That mask is what you feed into a compositor, a CNC or laser cutter, or a CSS mask-image rule. You also get a quick audit of the file: the share of fully transparent, semi-transparent and fully opaque pixels plus the alpha range, which tells you whether a PNG really has soft edges or was cut out with a hard 1-bit selection. Invert the mask or threshold it to a hard matte when you need crisp edges.

The alpha channel is read straight from canvas pixel data in your browser, so processing is 100% local and your artwork is never uploaded. Statistics are counted at full resolution, and the exported mask PNG matches the dimensions of the file you dropped in.

Frequently asked questions

What is an alpha channel?

The alpha channel is a fourth value stored alongside red, green and blue that records how opaque each pixel is, from 0 for fully transparent to 255 for fully opaque. Formats like PNG, WebP and GIF support it, while JPEG does not.

How do I turn transparency into a black and white mask?

Drop the image in and the tool writes each pixel's alpha value into all three colour channels, producing a grayscale image where white is opaque and black is transparent. Download that PNG and you have a mask any editor, compositor or cutting machine can read.

Why does my mask have grey edges?

Grey pixels are partly transparent, which is how antialiased cut-outs avoid jagged edges. If the workflow you are feeding needs a strictly two-value matte, tick the threshold option and everything above the cut-off becomes white while everything below becomes black.

Does a JPEG have an alpha channel?

No. JPEG has no transparency support at all, so every pixel is fully opaque and the extracted mask comes out solid white. The tool says so explicitly, which tells you the file simply has no transparency rather than the extraction having failed.

Is my PNG uploaded to extract the alpha channel?

No. The alpha bytes are read from canvas pixel data inside your browser and the mask is generated locally. Nothing is sent to a server, so confidential logos and client cut-outs stay private.

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