Polyhedron Software offers this limited free service allowing anyone to submit their
Fortran 77 source code and to view the converted and restructured
code after being processed using the SPAG feature of Polyhedron's PlusFort toolset.
The conversion options given here are only a very small subset of those available in
the full package and the only other limitation is that each routine is restricted to
Paste your code into the F77 code window, choose your conversion options and press SUBMIT. The converted code will appear in the F90 code window and a log of the conversion process can be viewed by pressing the 'show output log' button.
To view compile-time diagnostics for your Fortran source file, why not try Lahey's on-line Source checker