Fortran Standards Documents

Draft (unofficial) versions of the various recent Fortran standards and corrigenda are available from the J3 website, the WG5 website, in various formats. In addition, some older Fortran standards are available from The official standards can be bought from the International Organization for Standardization (ISO) or from your national standardization organization. In particular, ANSI's webshop often sells the standard for much less than ISO.

Documents of the format Nnnnn (e.g. N1830) are available from on the web server of WG5, documents of the form yy-nnnn (e.g. 04-007) or with an additional rn suffix indicating the revision (e.g. 97-007r2) are available from in the "year" subdirectory.

Note that, of these standards, GNU Fortran currently only supports the base Fortran 95 standard (not parts 2 or 3) as amended in the two corrigenda, the Fortran 95 TR 15581 extension, the Fortran 77 standard with the MIL-STD 1753 extensions, and some portions of the Fortran 2003 and 2008 standard; these standards have been highlighted in bold. The other documents are linked here for reference, but should not be taken as documentation of GNU Fortran features.

Fortran - Automatic Coding System for the IBM 704

Fortran 66

Fortran 77

Fortran 90

Fortran 95

Fortran 2003

Fortran 2008

TS 29113 Further Interoperability of Fortran with C

Note: ISO changed it from Technical Report (TR) to Technical Specification (TS)

TS 18508 Additional Parallel Features in Fortran

Fortran 2018

Fortran 2023

Other Relevant Standards

OpenMP (Open Multi-Processing)

OpenMP specifications - see also GCC's OpenMP project page

OpenACC (Open Accelerator)

OpenACC Specifications - see also GCC's OpenACC page


The IEEE standard covering Fortran 77 POSIX bindings is available online, though unfortunately only from locations with appropriate subscriptions to the IEEE server (e.g., many university networks). For those who do have such access, the link is:

POSIX Fortran 77 Language Interfaces (IEEE Std 1003.9-1992) (pdf)

Note IEEE 1003.9-1992 was withdrawn 6 February 2003. Some vendors provide their own way to access POSIX functions and make those available as module; for instance the IFPORT module of Intel or the f90_* modules of NAG. There also some compiler-independent efforts to make them accessible, e.g. Posix90 (doc), flibs' platform/files and directories, fortranposix.

ISO/IEC Project 22.24772: Guidance for Avoiding Vulnerabilities through Language Selection and Use

"The OWGV project is preparing comparative guidance spanning multiple programming languages, so that application developers will be better able to avoid the programming errors that lead to vulnerabilities in these languages and their attendant consequences. This guidance can also be used by developers to select source code evaluation tools that can discover and eliminate coding errors that lead to vulnerabilities."

IEEE 754

The IEEE Standard for Binary Floating-Point Arithmetic (IEEE 754) is the most widely-used standard for floating-point computation. Unfortunately, they are not freely available.

The IEEE 754-2008 standard has been adopted as ISO/IEC/IEEE 60559:2011

ISO/IEC 9899 Programming languages -- C

The C standard is relevant for two parts: (a) the interoperability features of Fortran 2003/2008/interop TR and (b) for the C Preprocessor (CPP; "Preprocessing directives"), which gfortran supports as vendor extension.

ISO/IEC 14882 Programming languages -- C++

ISO/IEC 8652 Programming languages -- Ada

Message Passing Interface (MPI)

Unified Parallel C (UPC)

None: GFortranStandards (last edited 2023-07-17 10:55:37 by TobiasBurnus)