Baseboard Calculator
Work out how much baseboard trim, also called base molding or moulding, or skirting board, you need. Enter the length and width of each room and the doorways, and the calculator finds the total length with waste and how many pieces to buy in the stock length you choose.
- Choose US or Metric. You can still change the unit of any single field.
- Enter the length and width of each room, and use Add room for the next one. For walls you measured one by one, choose Known length and enter their total.
- Enter the number of Doors and openings and their width. Leave the number blank if there are none.
- Choose the Stock length you'll buy, check the waste allowance, and enter a price per piece or by length to estimate the cost.
Length fields accept whole numbers, decimals, fractions, and mixed
numbers, such as 12, 10.5, 3/4, or
11 1/2. Choose ft + in as the unit to enter a
length such as 13 ft 6 in in two fields.
How to calculate baseboard
Baseboard runs along the floor around the room, so the length you need is the distance around the room, less the doorways:
Room length = 2 × (length + width) × quantity
Net length = total room length − doors and openings × opening width
Total length = net length × (1 + waste % ÷ 100)
Pieces to buy = total length ÷ stock length, rounded up
For a 12 × 14 ft room, 2 × (12 + 14) = 52 ft. Take off one 32 in door (2.67 ft) for 49.33 ft, and add 10% for 54.27 ft. That's 54.27 ÷ 8 = 6.78, so 7 pieces of 8 ft. Lowe's how-to guide for base moulding works the same way: measure each wall, add them up, deduct the doorways, and add 10% for waste and miter joints.
The pieces are counted from the total length, not wall by wall. Offcuts from long walls go on short ones, and a wall longer than one piece takes two pieces joined end to end, as Lowe's suggests.
How to measure for baseboard
Rooms
For a rectangular room, measure the length and width along the floor. An L-shaped room has the same distance around as the rectangle that holds it, so enter its overall length and width. For a U-shaped room, a room with angled or curved walls, or a hallway along one wall, measure each wall, add them up, and enter the total as Known length.
Square footage won't give you baseboard
The floor area doesn't tell you the distance around a room. A 144 ft² room is 48 ft around if it's 12 × 12 ft, but 60 ft around if it's 6 × 24 ft. So a house's square footage, such as 1,200 ft², can't tell you how much baseboard to buy. Enter the length and width of each room instead.
Doors and openings
Count the doorways and other gaps that get no baseboard, such as a closet opening. The opening width starts at 32 in, a standard interior door in the US, or 762 mm, a common internal door in the UK. The gap in the baseboard is a little wider, because it includes the door frame and the casing on both sides, so measure between the outside edges of the casing for an exact length. Starting from the door width takes off a little less than the real gap, so you won't come up short.
If your openings are different widths, add the widths together and enter them as one opening, or count them all at the narrowest width.
Stock lengths and waste
Baseboard is sold by the piece. Alexandria Moulding's primed baseboard comes in 8, 12, and 16 ft lengths. In the UK, Wickes sells skirting mostly in 2.4 m and 4.2 m lengths, and in Australia, skirting is often sold in 5.4 m lengths. The calculator starts at the shortest length, 8 ft or 2.4 m, so the count won't come up short if you buy longer pieces. Choose the length you'll buy, or enter it as a custom length.
The 10% waste allowance follows Lowe's and Alexandria Moulding, who both suggest adding 10% to the total. Rooms with many corners or short walls leave more offcuts, so raise it for those.
Examples
One room with a door
A 12 × 14 ft room with one 32 in door comes to 54.27 ft with 10% waste, or 7 pieces of 8 ft. That's $84.00 at $12.00 a piece. In 12 ft lengths, it's 5 pieces, and in 16 ft lengths, 4.
Two bedrooms and a hallway
Two 12 × 10 ft bedrooms (quantity 2) are 88 ft, and a hallway with 60 ft of wall brings it to 148 ft. Take off three 32 in doors (8 ft) for 140 ft, and add 10% for 154 ft, or 20 pieces of 8 ft.
A Metric room
A 4 × 3.5 m room with one 762 mm door comes to 15.66 m with 10% waste, or 7 lengths of 2.4 m. At £3.20 per m, that's £50.12. In 5.4 m lengths, it's 3.
FAQ
Add up the distance around each room, 2 × (length + width), subtract the width of each doorway, and add about 10% for waste. A 12 × 14 ft room with one 32 in door needs about 54.27 ft.
It depends on the rooms, not the area. Two rooms with the same floor area can need different lengths: a 12 × 12 ft room is 48 ft around, and a 6 × 24 ft room is 60 ft. Enter the length and width of each room to get the total.
Divide the total length, with waste, by the length of one piece and round up. For 54.27 ft, that's 7 pieces of 8 ft, 5 of 12 ft, or 4 of 16 ft.
Yes. Shoe molding and quarter round run along the bottom of the baseboard and stop at the same doorways, so they take the same total length.
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