The CMYK to Pantone tool on ginifab.com allows users to input a CMYK color code and recieve a list of PMS colors that are closest to the input color. Ngin.de also provides an accurate PMS color approximation tool that performs numerical calculations to convert CMYK colors into their PMS approximations.
CMYK is a color print process based on an additive method consisting of the four base colors: cyan, magenta, yellow and black. Pantone Matching System, also known as PMS, is a solid color matching system that blends colors to match those specified in the Pantone color guide. Due to the different processes behind the two systems, perfect color matches cannot be achieved when converting between CMYK and PMS; however, free approximation tools exist online.