Most "what's my color season" tools are quizzes: you tell them your hair is medium brown and they tell you what you just told them. Tone & Fit measures undertone, contrast and chroma from one selfie, names one of the 12 seasons, and shows how confident it is rather than pretending to be certain. You get 40+ named shades with hex codes you can paste into a shopping filter. Free in the browser, no account. Your photo is processed for the one request, then discarded.