5. Software

NGS Coordinate Conversion and Transformation Tool (NCAT) is an online package for performing coordinate conversion, and computes convergence and grid scale factor. Input and output can be interactive or file-based.

There's also a simple NAD 83 Coordinate Conversion Excel workbook I put together. It includes all the SPC zones (except Alaska) and UTM zones which cover the US. The workbook is handy If you're interested in the mathematics of conversions. Click here to download it.

I put together a summary document of NAD 83 SPC equations and parameters for CONUS. It can be downloaded from this link