What is the critical micelle concentration (CMC) in chemistry?

The critical micelle concentration is the point of surfactant concentration at which micelles form and all additional added surfactants go to micelles. 

Before reaching the CMC, surface tension is strongly affected by the surfactant concentration. After reaching the CMC, the surface tension is relatively stable regardless of the surfactant concentration. The CMC level is set depending on temperature, pressure, and on the presence of other surface active substances and electrolytes.