NAG Fortran Compiler IDE for Windows

Building projects using the NAG Fortran Builder is 'click of a button' simple. Subsequent builds only recompile those files that have been changed and their dependencies. And if the default options are not suitable, it is easy to change them using Project Settings. Incorporated in Fortran Builder is a GUI debugger to help solve any runtime problems. The debugging system makes quick work of correcting code allowing the user to get back to the work in hand.

Fortran Builder compiles and automatically links with an appropriate, licensed NAG Fortran Library or NAG Library for SMP & Multicore implementation. It also comes with precompiled LAPACK Libraries. The help system within Fortran Builder not only gives general advice but will also suggest the right compiler options for your scenario. It also includes an extensive Fortran language guide. 

Fortran Builder Key Features
  • Full coverage of Fortran 2008
  • Full parallel programming features of Fortran 2018
  • Call graph generator
  • Interface block builder
  • Informative runtime error messages
  • Precision unifier
  • Pretty Printer (polisher)
  • On 64-bit Windows systems, produces either 32- or 64-bit code
  • GUI debugger
  • Integrated help system
  • I/O library multi-threaded for performance
  • Improved Random Number Generator
  • Integrated NAG Library support
  • Additional integrated libraries: OpenGL, GTK+
  • Quick execution mode
  • Jump to location of runtime errors
  • Memory leak detection built into the compiler
Software Details


The help system within Fortran Builder provides full documentation. The help system not only gives general advice but will also suggest the right compiler options for your scenario. It also includes an extensive Fortran language guide.

  • Windows help (fortranbuilder.chm, see the security note and installation instructions, below.)

Due to security restrictions on help files, it is not possible to browse the Help file directly from the internet, however if you save the file locally (choose save rather than open if prompted by your browser) to a Microsoft Windows system, opening the help file for the NAG Fortran Builder from the local file system should open the file in Windows help. You will need to unblock help files copied from the internet before the first use. Select the local copy of the file using the right button. Select the properties tab and click the “unblock” button.


The NAG Fortran Builder projects include Console Application, Static Library, Dynamic Library/DLL and projects using various numerical libraries. Once the desired project type has been selected and named, files can be added to the project. Existing Fortran source files can be added to the project using the usual OS file opening dialogue. These files can be edited using the built-in Fortran-aware editor, which can also be used to create new files. The editor uses colour coding of syntax elements to make the source code more readable and features keyword completion.

Fortran Builder screenshots are available here.


Product Platform Release
the NAG Fortran Compiler
x86 and x86-64 Windows Release 7.1