Painting guides
The calculators give you the number. These pages give you the why, so you can argue with the number when your walls deserve it.
How far a gallon actually goesThe 350 vs 400 sq ft question, and the surfaces that drink your margin.
One coat or two?When one is honest, when two is mandatory, and when the wall wants three.
Measuring a room for paintPerimeter, height, deductions, and the stairwell problem, with a worked example.
Do I need primer?The five cases that need it, the one that doesn't, and which primer for which mess.