Check whether a skin is Classic or Slim
This Minecraft skin model detector estimates whether a modern 64×64 skin PNG was designed for Classic four-pixel arms or Slim three-pixel arms. It reads the texture locally, compares the UV positions used by the two arm layouts, highlights the evidence, and reports both a likely model and the strength of that evidence. The result is explainable: you can see the relevant pixels, inspect their coordinates, and understand why the estimate was produced.
The detector does not upload the image, attach it to a username, publish it, or change the source file. It is intended for a common practical question: you have a skin PNG but do not know which arm option to select in a game, viewer, editor, or converter.
Why the PNG does not provide a definite model label
Classic and Slim skins normally share the same 64×64 image dimensions. The difference is how the game maps parts of the arm texture onto geometry. Classic front and back arm faces are four pixels wide at standard resolution. Slim faces are three pixels wide, and neighboring side faces occupy adjusted positions in the atlas.
A plain PNG stores pixels, dimensions, color channels, and transparency. It does not contain a universal, authoritative field saying “this artwork is Classic” or “this artwork is Slim.” Some skin-pack formats can carry geometry metadata outside the PNG, and a game profile may remember a selected model, but a detached texture file often arrives without that context. Any tool that examines only the PNG must therefore infer intent from pixel placement.
That is why this page says “likely Classic” or “likely Slim” instead of claiming certainty. The wording is a feature, not a weakness: it accurately reflects what can and cannot be proven from a standalone image.
How Classic-only arm evidence works
The detector builds separate UV masks for the Classic and Slim layouts. It then finds atlas coordinates that belong to a Classic arm or sleeve face but are excluded from the corresponding Slim face. At standard resolution there are 64 Classic-only base-layer slots and 64 Classic-only outer-layer slots across both arms.
Opaque pixels in Classic-only base slots are the strongest direct evidence for Classic intent. A valid Slim renderer does not need those slots for its mapped base arm faces. If a design fills many of them and the complete Classic base layer has no transparent holes, the detector returns a strong Classic estimate. If only a few are occupied, it returns a moderate estimate because isolated pixels may be damage or leftover data.
Opaque Classic-only sleeve pixels are weaker evidence. Outer layers are optional, frequently sparse, and more likely to contain abandoned pixels from earlier edits. When only the overlay supports Classic, the detector reports limited confidence and tells you to review the file manually.
How likely Slim is estimated
If every Classic-only base slot is transparent, the file is compatible with the narrower arm footprint. The detector then checks whether all pixels required by the Slim base faces are opaque. A complete Slim base combined with transparent Classic-only columns produces strong Slim evidence.
This still does not make Slim mathematically certain. A Classic artist could intentionally erase an outer arm column, although doing so creates holes when the texture is rendered on Classic geometry. A deliberately transparent or nonstandard design can therefore resemble Slim. When the Slim base itself also contains transparent holes, the tool lowers its confidence because the file may be unfinished, damaged, or using unusual transparency.
The useful distinction is between “the pixel layout strongly fits Slim” and “the PNG contains official Slim metadata.” Only the first statement can be supported by this local analysis.
Reading the evidence map
After you select a 64×64 PNG, the page shows the original atlas next to a model evidence map. Orange marks identify opaque pixels in Classic-only base-arm slots. These directly support a Classic interpretation. Blue marks show the same base slots when they are transparent; a full blue pattern with a complete Slim base supports a Slim interpretation. Purple marks identify opaque evidence in Classic-only sleeve-overlay slots.
The report also lists sample (x, y) coordinates and labels each coordinate as base or overlay. Coordinates use a zero-based 64×64 grid: the top-left pixel is (0, 0) and the bottom-right pixel is (63, 63). You can use these positions in a pixel editor to inspect a suspicious seam or remove stray data deliberately.
The preview colors exist only in a temporary diagnostic canvas. They are not written into the selected skin, and this page does not provide a modified download.
Understanding the evidence strength
Strong Classic evidence means the detector found a meaningful number of opaque Classic-only base pixels and the Classic base faces were complete. Moderate Classic evidence means at least one Classic-only base pixel exists, but the pattern is smaller or the Classic base contains holes. Limited Classic evidence means only the optional sleeve overlay supports that interpretation.
Strong Slim evidence means no Classic-only base or overlay evidence was needed for the result and the Slim base faces were complete. Limited Slim evidence means the Classic-only columns are transparent but the narrower base layout also contains holes. In that case, neither model should be selected without looking at the arms in a viewer.
Confidence describes the structural pixel evidence, not artistic quality, file ownership, game acceptance, or platform approval. A strong result can still look wrong if the artwork was intentionally created for another model.
Files this detector accepts
The active model analysis requires an exact 64×64 PNG because the coordinate masks describe the modern standard atlas at that resolution. A 64×32 file is a legacy Classic layout with mirrored limbs, so it should go through the legacy converter before modern model analysis. A 128×128 texture is an HD atlas whose coordinates are scaled; use the HD-to-standard converter or a dedicated scale-aware workflow before relying on this report.
The file must decode successfully as PNG and must be no larger than the stated local limit. Renaming a JPEG to .png does not turn it into a valid skin texture. Unsupported inputs receive an error rather than being silently resized.
What can cause a misleading result
Transparent base artwork is the largest source of ambiguity. A Classic skin with an erased edge can appear Slim, while a Slim skin with stray pixels in unused Classic positions can appear Classic. Imported templates, partial recolors, format conversions, old editor behavior, and manually copied sleeves can all leave residual data.
Another source is model mismatch by design. Someone may have painted a texture while previewing Slim arms and later selected Classic in the game without converting the UV artwork. The detector describes what the pixels support; it cannot recover the creator’s unrecorded intention.
Finally, some renderers tolerate unusual transparency differently. The report is a structural comparison of standard UV masks, not a simulation of every game version, launcher, server plugin, resource pack, or skin-pack manifest.
Recommended verification workflow
Start with the detector and read the evidence reason, not only the model label. Check the highlighted arm columns and sample coordinates. Then open the local 3D skin viewer, select the estimated model, and rotate to the front, back, left, and right. Inspect shoulders, hands, sleeve seams, inner arms, and the outer layer.
Switch the viewer to the other model and compare. A wrong choice often reveals a missing strip, unexpected seam, compressed logo, or floating sleeve detail. If you decide that the source needs another geometry, use the matching Classic-to-Slim or Slim-to-Classic converter. Those tools rearrange arm UV faces; simply changing a model dropdown does not transform the atlas.
After conversion, review the generated or removed edge, open the result in the pixel editor for manual correction, and run the general skin checker for base holes and pixels outside mapped faces. Preserve the original PNG under a separate filename so the workflow remains reversible.
Privacy and platform limits
The selected texture is decoded into browser memory. Pixels, filename, evidence coordinates, and the diagnostic preview are not sent to an image upload endpoint. Leaving or refreshing the page clears the active in-memory result. No registration, profile, cloud project, or database record is created.
Local privacy does not guarantee that a later game import will succeed. Account settings, edition differences, server rules, skin-pack metadata, moderation, and content rights remain outside this detector. SkinEditor.org is an independent tool and is not an official Minecraft product or service. It is not approved by or associated with Mojang or Microsoft.
Frequently asked questions
Can a detector be 100 percent certain from a PNG?
No. A standalone PNG normally lacks authoritative Classic or Slim metadata. Pixel positions can provide strong evidence, but transparent art and stray data can imitate the other layout.
Does this tool convert the arm model?
No. It analyzes and explains the likely source model. Use the linked model converter only after you decide that the artwork needs a different arm geometry.
Why does a likely Slim result mention Classic holes?
The Classic layout requires additional base-arm columns. Their transparency appears as Classic base holes while remaining normal unused space for Slim. Comparing both hole counts helps explain the estimate.
Is a purple overlay pixel enough to prove Classic?
No. Overlay-only evidence receives limited confidence because optional sleeves often contain leftovers. Confirm it in both model previews.
Does the evidence map alter my skin?
No. The colored map is a temporary visualization. The original PNG remains unchanged and is not uploaded.