Thankfully, there are very few scientific equations in interior design. In my opinion, creating your space is quite simply down to what you love and what you think works.
With one exception - Lampshades.
The question I get asked a lot is how much fabric do I need to make a lampshade and what size base do I need for my shade? Well if you are going for a standard 30cm drum or tapered shade your fabric needs to be a metre long and half a metre wide.
In terms of the proportions, the clever people at Architectural Digest recommend, 'Measure the base and height of your lamp, the shade should be twice as wide as the lamp base and one-third of the total height of the lamp.'
Hope this helps and as always do share any of your creations with us!