Four inside corners do not add sticks by themselves. They add cuts, which is what the percent is for. Paint for the trim, if you are painting it, is a small part of the paint calculator. The floor those boards sit on is flooring.
FAQ
How many sticks of baseboard?
Perimeter is 2 × (length + width), minus the door openings. A 12 by 10 room with a 3 foot door is 41 feet. Ten percent is 45.1 feet. In 16 foot sticks that is 3.
Crown molding?
Same sticks if you measure the same perimeter. Crown sometimes needs more waste because the miter is steeper. Raise the percent. Quarter round at the floor is the same linear feet as the base, usually with less waste.
Sources
- NIST Handbook 44: The foot. Stick length is whatever the store sells, often 8, 12, or 16.