Many years ago I worked for a web developer, we used Filemaker Pro. If you have never tried Filemaker I strongly advise giving it a go as it is the most amazing program, yes its a data management suite but so powerful with the ability to be cloud based as well as phone apps; it’s free to try 🙂 https://www.filemaker.com/
I digress a little, but in the process of rebuilding my website I have been learning new skills and re learning some old ones, oh boy HTML has changed a lot over the years.
On my journey I found a great website that has been walking me through creating an online calculator. I thought it might be nice to have a little Amatuer radio formula here for people to learn and play with, if you interested in JAVA or CSS have a look here: https://codeburst.io/ its a great website with easy to follow tutorials.