This is the reverse of the usual lookup: instead of feeding in a CMYK mix and finding the closest Pantone, you pick the Pantone reference you have been given and read off the values you need to reproduce it. That is the more common situation in practice, since brand guidelines specify a Pantone number and leave you to work out what to put into a document. Select a reference and you get its approximate CMYK breakdown, HEX and RGB for screen work, and LAB values for anyone doing colour management properly. The page also computes two things that are usually left out. It gives the WCAG contrast ratio against white and black, which tells you immediately whether the colour is usable as body text or only as a background or accent, and it lists the nearest other references by CIE76 difference, which is useful when the exact ink is unavailable or out of budget. The honest caveat is that this is an approximation and always will be. Pantone colours are premixed spot inks, and many of them sit outside the CMYK gamut entirely, which is why a printed CMYK simulation of a vivid Pantone orange never quite matches the swatch. For anything where colour accuracy is contractual, check against a physical swatch book. For the other direction see CMYK to Pantone Converter, and for the full list see Pantone Color Chart.
CMYK to Pantone conversion is a routine step in professional print production. When a design is built in process color (CMYK) but a specific element must be reproduced as a Pantone spot color for brand consistency or special finishing, the designer needs to identify the nearest Pantone equivalent. Brand guidelines routinely specify both a Pantone number and CMYK breakdown: the Pantone number for spot color jobs, the CMYK values for full-color offset or digital print. When these are not cross-referenced in existing documentation, this converter identifies the closest Pantone Solid Coated match for any CMYK combination. The CIE76 ΔE color difference scale works as follows: ΔE below 2 is imperceptible to most observers; ΔE 2 to 4 is noticeable only when the two colors are placed directly side by side; ΔE above 6 is a clearly visible difference at normal viewing distance. High ΔE values are expected for saturated mixed colors that fall outside the gamut of standard Pantone inks. In these cases, the converter result is a useful starting point, but the final spot color selection should be confirmed against a physical Pantone swatch book under the intended lighting conditions. For converting between digital color formats, use Color Converter. For building a complete color palette from a brand color, use Tint & Shade Generator or Color Palette Generator.