This is a super simple energy usage and bill calculator.
I built this because I was going through the hell on earth that is dealing with my energy provider and I needed a fast and simple way to calculate my energy usage and what I should owe based on my meter readings.
Also why do maths when a computer could do it for you?
Check out a demo here.
The calculations are based on the UK energy bills but could be modified for elsewhere.
This code is a little messy I know, but it works, I didn't have much time to do this, please feel free to improve it.