Fortran Calculus Compiler: Calculus level computer languages are Fortran Calculus and PROSE. Both languages are based on what is called "Automatic Differentiation" (AD). Calculus languages simplify computer coding to an absolute minimum; i.e., a mathematical model, constraints, and the objective function. Minimizing the amount of code allows the user to concentrate on the science or engineering problem at hand and not on the (numerical) process requirements to achieve an optimum solution. Major benefits from AD based software are: o Determines Optimal solutions o Allows Rapid Model Prototyping o Accelerates Problem "Understanding" o Increases Engineering Output and Quality o Reduces Time & Costly Problem / Solution Cycle Fortran Calculus was designed to solve implicit problems. Implicit problems are abundant in every branch of science and technology, the most common being data fitting problems. Simulation programs can be elevated to optimization programs by using the FIND statements. An example circuit simulation program was converted and showed a 90% reduction in development time. Simulation conversions seem to have the most to gain besides those problems that can only be solved with this tool. PDEs, ODEs, and Algebraic equations can be solved. For cost savings, optimum solutions, and increased engineering output, consider Fortran Calculus.