The GNU Fortran ( gfortran ) compiler is the gold standard for free, open-source Fortran development. It is part of the GCC (GNU Compiler Collection) and fully supports FORTRAN 77, Fortran 90, 95, 2003, and 2008 standards.

Includes a built-in IDE (Plato) and excellent debugging tools.

This is the most popular open-source choice. It is part of the GNU Compiler Collection (GCC) and fully supports Fortran 77 alongside modern standards. How to Get It : You can download it through , which provides a 64-bit environment for Windows.

FORTRAN 77 remains a cornerstone of scientific computing, engineering, and legacy software systems. If you need to run, debug, or maintain classic Fortran code on a modern 64-bit Windows 10 environment, finding a compatible, free compiler can be challenging. Modern operating systems do not natively support the 16-bit or 32-bit compilers of the past.

By following this guide, you should be able to download and install a Fortran 77 compiler on Windows 10 64-bit and start developing your own Fortran 77 programs. Happy coding!

Then compile Fortran 77 code exactly as on Linux.

FORTRAN 77 remains a cornerstone of scientific, engineering, and legacy computing. Finding a native, free 77-specific compiler for modern 64-bit Windows 10 can be challenging because most modern tools bundle Fortran 77 compatibility into Fortran 95 or newer compilers.

Silverfrost FTN95 is a dedicated Windows Fortran compiler that offers full compatibility with FORTRAN 77. The Personal Edition is completely free for personal and educational use.

Look for the "codeblocks-XX.XX-fortran-setup.exe" on the Code::Blocks binary releases page .

Download the free editor and install the Modern Fortran extension for syntax highlighting, debugging tools, and code completion features. If you want to customize your setup further, let me know:

It is designed specifically for Windows, allowing for easy compilation and creation of Windows GUI applications via ClearWin+. It is often considered easier to set up for beginners than MinGW. 3. Open Watcom V2

is a free, simple IDE specifically designed for Fortran. It’s very lightweight and uses the G77 or GFortran back-end. While it hasn't been updated in years, it is frequently used in academic settings because it is incredibly straightforward for compiling single .f or .for files. 4. Silverfrost FTN95 (Personal Edition)

Compile & run (gFortran example):

hello.exe