There are a lot of compilers/editors/tools that allow you to use fortran, a big number of these is in the Public Domain/Open Source/ BSD Licence/…/… world:
This system comes with the GNU G77 Fortran compiler (among other things, including a C/C++ compiler), which you can use to generate Win32 executables from F77 code. Like many systems based on the GNU tools, Mingw32 comes with complete with various programming tools, such as a program maintainence program (ie, make), text processing tools (sed, grep), lexical analyser generator (flex), parser generator (bison), etc.
The Intel Fortran Compiler for Linux is free for personal, non-commercial use (registration required). It features an optimizing compiler, the Intel Debugger (GUI and command-line), mixed language support (C and Fortran), full compliance with the ISO Fortran 95 standard, support for the evolving Fortran 2003 standard, multi-threaded application support (OpenMP and auto-parallelization), ability to handle big-endian data files, compatibility with various Linux tools (like make, gdb and Emacs), substantial compatibility with Compaq Visual Fortran, etc. The optimizing compiler supports interprocedural optimization, profile guided optimization, automatic vectorizer, etc.
G95 is a stable, production Fortran 95 compiler available for multiple cpu architectures and operating systems. Innovations and optimizations continue to be worked on. Parts of the F2003 standard have been implemented in g95.
Gfortran is the name of the GNU Fortran project, developing a free Fortran 95/2003 compiler for GCC, the GNU Compiler Collection. The gfortran development effort uses an open development environment in order to attract a larger team of developers and to ensure that gfortran can work on multiple architectures and diverse environments.
It is available for the following architectures:
- x86-linux, x86_64-linux
- Windows (x86, cygwin and mingw; amd64-mingw)
- MacOS X, Intel and PowerPC (powerpc-darwin and i386-darwin)
- x86-freebsd, amd64-freebsd, x86-openbsd
- IA64-linux, IA64-hpux
- sparc-solaris, i386-solaris
- alpha-linux, Tru64
- mips-irix, mips-linux
- hppa-linux, hppa-hpux
Force is a free IDE for the FORTRAN 77/90 programing language.