This calculator is for hanging paintings, assuming mirror plates are already on the canvas and the desired horizontal position on the wall is decided. Input both your eye level (or leave at the default value) and the height of the canvas then hit calculate. This will return the height of the bottom of the art from the floor, so all you need to do is mark the point, rest the art at this point on a spirit level and drill through where the holes on the mirror plates are. Use the tab and enter keys for quick use on the computer. This calculator is superflous if hanging one or two paintings, but if tasked with hanging lots of paintings in a gallery then this calculator should save you a lot of time when doing the same calculation over and over.
I tested this idea with ChatGPT and was able to quickly throw this online. This calculator is most useful in the scenario that you are a technician in an art gallery and it's your job to put up a load of paintings with mirror plates, and the curator has marked where specifically. This first iteration of the calculator assumes the mirror plates are correctly screwed into the frame; all you need to do is quickly measure the height of the frame, divide it by two then subtract that from the eye level to mark the bottom. This just saves your thumbs, your time and reduces risk of mistakes.
The second iteration to come of this calculator is rarer scenario that you have to hang a painting on a wire. This requires more inputs and outputs. Work in progress.
So why did I make this. Well I'm currently on a work placement and this situation presented itself to me. There was a lot of measurements to calculate and mark on the wall. That algorithm, 155cm - height/2 is the first thing to tackle. We knew where the left side of the canvas should sit. So measure up with the meter-and-a-half stick, measure down half the height, then you got your bottom. Then you level it with the spirit level, and drill in the holes where the mirror plates are. Often we would have to mark where the left side is up from the mark the curator made. There had to be a better way.
With my method, the user can measure the height of the painting, input the value to the website (probably on their phone which I aim to optimise), hit calculate and they get the height where the bottom of the painting should sit. This might seem superfluous but I found communicating maths can get so tricky between two or more people. My mind boggled on the day, but I asked myself after, "Why can't I just use the algorithm of getting the eyeline to get the bottom, put it at the space where the curator wants it, rest the art on the level at the bottom, get it straight and drill it in?". So I made this website before even checking online to see if one exists. Now that I am writing this I see they do exist but from what I've seen they are aimed at people doing one painting who want some help with the maths. It wouldn't be appropriate for use by a technician because there were two many inputs required, like where the plates are on the canvas.
This website is a work in progress for me. I really hope this might come in handy some day to some one. I will keep editing this site to include calculators for other possibilities.
Lewis Owen