I do this in HTML with Vue. It lends itself pretty well to building calculators. Those calculator templates are self-contained, so I just use them all over my website.
Perhaps there are tools that do this, but the use case is fairly simple: variable substitution based on user input. For that, I'd stick to simple, client-side tools.
See here: https://allaboutberlin.com/tools
Perhaps there are tools that do this, but the use case is fairly simple: variable substitution based on user input. For that, I'd stick to simple, client-side tools.