REAL(16) (same as REAL(KIND=16)) data occupies 16 contiguous bytes stored in IEEE-style X_floating format. Bits are labeled from the right, 0 through 127, as shown below.
The form of REAL(16) data is sign magnitude, with bit 127 the sign bit (0 for positive numbers, 1 for negative numbers), bits 126:112 a binary exponent in excess 16383 notation, and bits 111:0 a normalized 113-bit fraction including the redundant most-significant fraction bit not represented.
The value of data is in the approximate range: 6.4751751194380251109244389582276465524996Q-4966 to 1.189731495357231765085759326628007016196477Q4932. Unlike other floating-point formats, there is little if any performance penalty from using denormalized extended-precision numbers. This is because accessing denormalized REAL (KIND=16) numbers does not result in an arithmetic trap (the extended-precision format is emulated in software). The smallest normalized number is 3.362103143112093506262677817321753Q-4932.
The precision is approximately one part in 2**112 or typically 33 decimal digits.