Check before you publish
Transparent PNG Checker
Find out whether your PNG contains real transparency or just looks transparent. Read its pixel counts and compare three background previews without uploading or changing the file.
Local pixel analysis. Your file is not uploaded. Up to 10 MB, 8,192 px per side, and 16 megapixels. Animated PNG is evaluated only as the browser-decoded frame.
A real source and cutout, on three surfaces
These are the existing diagnostic source and the actual output of our local background remover. The cutout is shown twice with different background colors; these are inspection views, not separate generated results. Use the sample buttons above to reproduce the counts.
1. Inspect the file you will actually deliver
Choose the downloaded PNG, rather than a screenshot of the editor preview. A screenshot can turn a transparent canvas into an opaque checkerboard. The checker validates PNG bytes and counts the original decoded pixels without resizing. A PNG extension alone does not establish that a file contains transparency.
2. Read the three alpha counts
Fully transparent pixels have zero opacity; opaque pixels completely cover the surface behind them. Partly transparent pixels blend with that surface. The categories add up to width × height. A file can be a valid PNG while every pixel is opaque, so a successful decode is not evidence of a transparent background.
3. Treat partial transparency as a clue
Soft edges, shadows, and anti-aliasing can legitimately create partly transparent pixels. Their presence is not automatically an error. Inspect where they occur: a soft subject edge may be useful, while a faint rectangle around the entire image can be leftover background. Counts alone cannot make that distinction.
4. Compare light and dark surfaces
The previews place the same unmodified image over white, dark blue, and pink. Look for white fringes on the dark surface and dark residue on white. Pink makes holes in the subject easier to spot. The checker fits the image into each panel, so open the original in an editor for pixel-level inspection of very fine edges.
5. Recognize a painted checkerboard
If the result says there are no transparent pixels and checkerboard squares remain visible across every preview, those squares are likely baked into the image. Changing the filename will not remove them. Find the original transparent asset or recreate a cutout from an authorized source image.
6. Keep a transparent master
After correcting the background, download a fresh PNG and check it again. Preserve that master before making flattened copies for platforms that require JPEG. If a destination converts the asset, inspect the actual downloaded delivery file; a clean local original does not prove that a platform kept its transparency.
What this check can and cannot prove
The tool reports decoded alpha at browser precision. It does not certify clean subject edges, inspect metadata, identify copyright ownership, or validate all frames of an animation. Small transparency percentages can mean either a tiny intended gap or incomplete background removal. Use the counts together with visual inspection.
Technical reference: W3C PNG specification, which defines PNG transparency and alpha.
PNG checker FAQ
Does a white preview mean my PNG is opaque?
No. A viewer may place transparent pixels on white. Check the alpha counts and preview on another color to distinguish transparency from white pixels.
Is my PNG uploaded?
No. The checker decodes your selected PNG and reads its pixels in your browser. Sample buttons download public example files; your selected file stays local.
Does this remove the background?
No. It inspects the file without editing it. Use the linked background remover if you need a cutout.
Can it verify every frame of an animated PNG?
No. It analyzes the browser-decoded frame, not all animation frames. It is intended for still PNG assets.