IEEE floating point
From Just Solve the File Format Problem
IEEE floating point, or IEEE 754, is a set of standard binary (meaning non-text) formats for binary (meaning base-2) and decimal floating point numbers. The IEEE 754 standard also defines rules for processing such numbers.
The 32-bit and 64-bit formats for binary numbers are used in countless file formats.
There are at least two revisions, IEEE 754-1985 and IEEE 754-2008. The standards documents are not freely available, though the interchange formats are well known.