It's actually very easy to make Fortran bindings for Julia, where you can call your Fortran code from Julia. https://docs.julialang.org/en/v1/manual/calling-c-

It's actually very easy to make Fortran bindings for Julia, where you can call your Fortran code from Julia. https://docs.julialang.org/en/v1/manual/calling-c-and-fortran-code/#Fortran-Wrapper-Example https://docs.julialang.org/en/v1/manual/calling-c-and-fortra... So unless you think the Julia version will compile to faster code than the Fortran code (probably not if you use a fancy paid license Fortran compiler), then definitely don't rewrite.