Intrinsic functions are supplied automatically by the system and can be used in expressions in any program unit. A description of their special properties appears in section 9.1.

Many of the arithmetic intrinsic functions have generic names: that is they can be used with several different types of arguments. The SQRT function, for example, can be used with a real, double precision, or complex argument. The Fortran system automatically selects the correct specific function for the job: SQRT, DSQRT, or CSQRT. These specific names can be ignored in almost all circumstances, and are listed only in the appendix. In most cases the data type of the function is the same as that of its argument but there are a few obvious exceptions such as the type conversion functions.

In the descriptions below, the number and data type of the arguments of each intrinsic function are indicated by a letter: I = integer, R = real, D = double precision, X = complex.

An asterisk on the left indicates that the result has the same data type as the arguments. Note that if multiple arguments are permitted they must all have the same data type. Thus I = NINT(RD) indicates that the NINT function can take a single real or double precision argument but its result is always integer, whereas * = ANINT(RD) indicates that the result has the same type (real or double precision) as the argument.

- Trignometric Functions
- Other Transcendental Functions
- Type Conversion Functions
- Minimum and Maximum
- Other Functions