I've decided to tackle the job of recovering our sofa myself. I may be back with lovely pictures, or I may be on another thread asking for new sofa recommendations 
If I give the measurements, would anyone have a rough idea how much material to start with? Between MIL and I, we have tons of material stashed away, but I don't want to start and then realise I don't have enough of one particular colour for example.
So, the sofa dimensions are roughly:
W - 190cm
H - 82cm
D - 100cm
Then there would be two seat cushions of similar width/depth of sofa, plus four back seat square cushions at about 45x45cm each.
Any advice would be handy! Thank you.