Double is a 64-bit, floating-point data type used to store precise decimal numbers. They can hold values in a range of -2.2E-308 to +1.7E+308. Its precision is of 15 decimal digits. They are similar to Single data types but more precise and with an extended range.

Doubles have a greater range and precision than Singles, they still have limited accuracy which can lead to significant inaccuracies if not used properly. They are dyadic numbers - i.e. they can only accurately hold multiples of powers of two, which will lead to inaccuracies in most base-10 fractions.