Datatype for floating-point numbers larger than those that can be stored in a float. A float is a 32-bit values that can be as large as 3.40282347E+38 and as low as -3.40282347E+38. A double can be used similarly to a float, but can have a greater magnitude because it's a 64-bit number. Processing functions don't use this datatype, so while they work in the language, you'll usually have to convert to a float using the (float) syntax before passing into a function.


  • double a;             // Declare variable 'a' of type double
    a = 1.5387D;          // Assign 'a' the value 1.5387
    double b = -2.984D;   // Declare variable 'b' and assign it the value -2.984
    double c = a + b;     // Declare variable 'c' and assign it the sum of 'a' and 'b'
    float f = (float)c;   // Converts the value of 'c' from a double to a float


  • double var
  • double var = value


  • varvariable name referencing the float
  • valueany floating-point value