How this calculator works
The wainscoting covers the wall length less the doors. Each board is a piece as tall as the wainscoting, and covers its own width, so the pieces to cut are the length of wall divided by the width a board covers, plus an allowance for cutting. A plank is cut into as many pieces as will fit in its length: an 8 ft plank gives two pieces of 36 inches. The cap rail runs along the top of the boards for the whole length.
Worked example: 40 ft of wall less 6 ft of doors is 34 ft, which takes 82 pieces of 5.5 inch board, 36 inches tall. An 8 ft plank gives two pieces, so that is 41 planks. The boards cover 102.0 sq ft, and the cap rail is 34 ft (5 pieces of 8 ft). With no doors it would be 96 pieces. A taller 50 inch wainscoting gives only one piece from a plank, so it needs 82. With narrower 3.5 inch boards it is 129 pieces and 65 planks. From 4 ft planks the 36 inch boards give one piece each: 82 planks. A small room with 24 ft of wall and a door takes 26 planks.
Wainscoting boards for common rooms (36 in tall, 5.5 in boards, 8 ft planks, 10% extra, one door of 3 ft)
Pieces to cut, planks to buy and the cap rail.
| Wall length | Pieces | Planks | Cap rail |
|---|---|---|---|
| 20 ft | 41 | 21 | 17 ft |
| 30 ft | 65 | 33 | 27 ft |
| 40 ft | 89 | 45 | 37 ft |
| 50 ft | 113 | 57 | 47 ft |
| 60 ft | 137 | 69 | 57 ft |
| 80 ft | 185 | 93 | 77 ft |
Tips before you buy
- Mark the height on the wall with a level line all the way round, since floors are rarely level.
- Fix the boards to the studs, or use construction adhesive on the wall as well as nails.
- Cut around the outlets and switches before you fix the boards, and fit box extenders if needed.
- Paint the boards before you fit them, and fill the nail holes and the joint with the cap rail at the end.
- Leave a small gap at the floor for the baseboard to cover.
Tools & materials for this project
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Frequently asked questions
How much wainscoting do I need?
The wall length less the doors, divided by the width a board covers: for 34 ft of wall and 5.5 inch boards, 82 pieces, which is 41 planks of 8 ft.
How high should wainscoting be?
About a third of the height of the wall: 32 to 36 inches for 8 ft ceilings. A 36 inch height lets you cut two pieces from an 8 ft plank.
How many pieces do I get from a plank?
Two for a 36 inch wainscoting from an 8 ft plank, and one if the wainscoting is taller than 48 inches.
How much cap rail do I need?
The same as the length of wall covered: 34 ft, which is 5 pieces of 8 ft with 5% extra.
Do I need to leave out the doors?
Yes, subtract the width of each door and opening at floor level, and add extra for cutting around outlets and corners.
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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.