Eighteen degrees Celsius equals 64 degrees Fahrenheit. It is possible to convert Celsius to Fahrenheit by multiplying the Celsius value by 9, dividing the result by 5 and adding 32.
Named after a German scientist, G.D. Fahrenheit, the Fahrenheit scale has two set points: the freezing and boiling points of pure water when at sea level, which are 32 and 212 degrees Fahrenheit, respectively. The International System of Units, or SI unit, for temperature is Kelvin. As of 2015 SI units are used by the majority of countries worldwide. According to the Kelvin scale, the boiling and freezing points of pure water at sea level are 373.15 and 273.15 Kelvin, respectively.