So I know that probably a bazillion of these exist online, but I can't be bothered to find them, but I can be bothered to spend 10 minutes proompting ChatGPT to make a quick website to calculate them from me. For some reason, it's just a day ahead???? So I unfortunately had to do some thinking and edit the javascript :(
Nevertheless, enjoy I guess :)
And yes, ChatGPT made almost the entirety of this, except for obviously these paragraphs of text and the very small changes I made to its js. Yes, that does mean it made this CSS! Which I have to admit is better made than my CSS :|