About the Baseboard Calculator
Baseboard — called skirting board in the UK — is the strip of trim that runs round a room where the wall meets the floor. It covers the expansion gap at the edge of the flooring, hides an uneven junction and protects the bottom of the wall from knocks and vacuum cleaners. It is also one of the most satisfying finishing jobs in a renovation, because it makes a room look complete.
Working out how much to buy is a matter of measuring round the room, but there are three details that decide whether you have enough: the door openings, where the baseboard stops, the corners, each of which is a cut that uses a little extra, and the lengths the boards come in, because joints are best kept to a minimum.
This baseboard calculator works out the perimeter, takes off the doors, adds a waste allowance, divides by the board length, and counts the corners and finishing nails.
How to Use the Baseboard Calculator
Choose metric or imperial.
Enter the room's length and width. For rooms that are not rectangles, enter a length and width with the same total perimeter, or run the calculator for each part.
Enter the number of doorways and the width of each opening, including the door casing or architrave on both sides.
Enter the board length you plan to buy.
Optionally, enter the number of outside corners — around chimney breasts, bays and wall nibs — and adjust the waste allowance.
How the Boards Are Worked Out
perimeter = 2 × (length + width)
baseboard = perimeter − doors × door width
boards = baseboard × (1 + waste %) ÷ board length, rounded up
nails = baseboard ÷ stud spacing × 2Step-by-Step Example
A 5 × 4 m room with one 0.9 m door, 2.4 m skirting, 10% waste.
Perimeter: 2 × (5 + 4) = 18.00 m
Less the door: 18.00 − 0.90 = 17.10 m
With waste: 17.10 × 1.10 = 18.81 m
Boards: 18.81 ÷ 2.4 = 7.84 → 8 boards
Nails: 17.10 ÷ 0.4064 → 43 studs × 2 = 86 nailsIn a 15 × 12 ft room with two 3 ft doors, the same working gives 48 ft of baseboard, and four 16 ft lengths.
Measuring a Room
Measure each wall at floor level, from corner to corner. Walls are not always straight, and a measurement taken at waist height can differ by a surprising amount from one taken at the floor.
Include every return: alcoves either side of a chimney breast, the sides of a bay window, the short walls around a boxed-in pipe. Each adds a few centimetres and a pair of corners.
Measure doorways across the full opening including the casing on both sides, because the baseboard butts into the casing rather than running across it. Fitted cupboards and kitchen units that sit on the floor also need no baseboard behind them.
Corners: Cope or Mitre?
Every corner is a joint between two boards, and how it is cut matters more than anything else for the finished look.
Inside corners are best coped. One board runs tight into the corner; the other is cut to the exact profile of its face with a coping saw, so it sits over it like a jigsaw piece. A coped joint stays closed even when the corner is not quite 90° or the wood shrinks a little.
Outside corners are mitred — both boards cut at 45°, or at half the actual angle if it is not square — then glued and pinned together.
Where one wall is longer than your boards, join lengths with a scarf joint: two 45° cuts that overlap, ideally over a stud. Unlike a square butt joint, a scarf joint does not open into a visible gap when the wood moves.
Choosing Board Lengths
Buy lengths long enough to run each wall in one piece where you can. A room with 4.2 m walls is neater with 4.2 m skirting than with 2.4 m lengths joined in the middle of every wall, even if the total footage is the same. In North America, 16 ft baseboard covers most walls without a joint; in the UK, skirting commonly comes in 2.4 m to 4.2 m lengths.
Fixing and Finishing
On timber-stud walls, baseboard is nailed into the studs and the bottom plate with finishing nails, two at each stud. On masonry walls it is usually fixed with grab adhesive, sometimes with screws into plugs as well. Fill the nail holes, caulk the top edge where it meets the wall, and paint or finish.
Pre-painting or priming the boards before fitting — and touching up afterwards — is much quicker than painting them in place.
Understanding Your Result
Boards needed is the number of lengths to buy.
Length shows the perimeter, the baseboard after doors, and the total with waste.
Corners counts the inside and outside corners.
Nails estimates finishing nails at two per stud.
Worth knowing covers joints between lengths.
When Should You Use This Calculator?
Before buying baseboard or skirting for a room or a whole house.
After fitting new flooring, when the old skirting has been removed.
Pricing a job, with the nails and caulk.
Comparing board lengths, to see how many joints each needs.
Common Mistakes
Forgetting alcoves and returns. Each adds length and corners.
Not deducting doorways. You buy baseboard you cannot use.
Mitring inside corners. Coped joints stay tighter.
Butt-jointing long walls. Use a scarf joint over a stud.
Buying short lengths to save money. More joints, more waste.