Follow this room’s arithmetic
The two 20-foot walls and two 24-foot walls total 88 feet. This example deducts 2 baseboard-free openings, each 36 inches wide. At 12 inches per foot, that removes 6 feet. The remaining 82 feet is the installed length before cutting allowances.
Net: 88 − (2 × 36 ÷ 12) = 82 ft
Budget: 82 × 1.15 = 94.3 ft
Selected pieces: ceil(94.3 ÷ 12) = 8
Purchased: 8 × 12 = 96 ft
Compared with the net installed length, those selected pieces provide 14 extra feet. That includes the percentage allowance and any additional length created by rounding up to whole sticks. It is not a promise that every leftover section will fit elsewhere. No price or material rate has been assumed, so this page does not supply a dollar total.
What the corners mean here
A plain rectangle has four inside corners and no outside corners, which are the counts shown above. Door jambs are ends of baseboard runs, not extra room corners. If your room has a projecting column, recess, or return, switch to measured wall lengths and enter the actual inside and outside turn counts. This example contains no hidden extra corner length or corner accessory cost.
Compare the other allowance
Changing just the allowance to 10% produces 90.2 budget feet and 8 pieces of the same 12-foot stock. The piece count stays the same because both totals fit within the same whole-stick boundary. Decide between 10% and 15% by checking your actual cut layout, material condition, and preferred spare length.
Before you turn this into a cut list
Each 20-foot and 24-foot wall still needs its own measurements at the baseboard line. The opening positions are unspecified; placing a door in the middle of a wall creates different cut lengths from placing it next to a corner. Mark those runs on a sketch, plan any joints, and allow for saw kerf. A long run may need a joint when it exceeds the selected stock length. Reusing short pieces can make a total-length estimate practical, but that reuse must be checked against the sketch.
Read the measuring guide, formulas, common mistakes, and FAQ. The adjustable calculator preserves all of this example’s inputs and lets you enter a price for your actual supplier’s stock.