I already use the Windows 10 app Calculator that comes preinstalled, and the scientific mode works fine for what I need it for, for the most part.
What I need is a Windows program that has all the functionality of the above, as well as the ability to add extra buttons for calculations that I do frequently. Simple stuff like 1-x, and if possible, slightly more advanced use of storage variables for time conversion, etc.
In terms of UI I'm thinking either a drag and drop type of thing or a set of unused buttons that can be labeled and given functions of my own.
The closest programs I've found to what I need are:
Which has "macros" that seem to just amount to pasting in a set of characters, with no possibility of directly affecting what I've already typed.
An android app that has drag and drop buttons but you can only choose from a collection of possible functions, with no ability to add your own.
I've also heard of making a calculator from scratch using Python, which while not entirely out of the question, it would require me to learn a new programming language. I've already programmed a few things, but not in Python. A slightly better solution would be if there is an open source calculator of this kind that can be built upon.
galculatorwhich can do this easily, but it is a *nix-program... but anyway cygwin is mentioned at the homepage and maybe you can built upon its source since it is FOSS under GPL2.