Carpet broadloom calculator
Enter the room dimensions, pick a roll width, set wastage. The calculator returns linear metres to order and flags whether a join is needed.
Inputs
Result
How the calculation works
The shorter room dimension must fit within the roll width to avoid a join. The calculator orients the room so the longer dimension runs along the roll length, then multiplies by (1 + wastage / 100) for the linear metres figure. If both room dimensions exceed the roll width, multiple drops are required and a visible join is unavoidable — plan its position before you cut.
Quoting a whole house in carpet across multiple rooms? Use the multi-room carpet cut list calculator — same maths applied across every room and totalled into one linear-metre figure. Or mark each room from the floor plan in AreaSum and the report rolls totals up per room, ready to drop into the cut list. See how it works.
New to the trade terms? Read up on broadloom carpet, broadloom roll width, linear metres and wastage allowance — or jump to the audience guide for carpet retailers.
The two Australian broadloom widths (3.66 m and 4 m) drive every seam and wastage decision on a carpet job. The broadloom carpet glossary entry covers the format, pricing (m² vs lm), and how it compares to carpet tiles.
Broadloom carpet — frequently asked questions
- How many linear metres of carpet do I need for a room?
- The linear metres equal the room’s longer dimension plus wastage, provided the shorter dimension fits within the roll width. A 5 m × 3 m room on a 3.66 m roll (the 3 m side fits) needs about 5 m + 10% ≈ 5.5 linear metres. Enter your dimensions above and the calculator returns the figure.
- Will my room need a carpet join?
- Only if the shorter room dimension is wider than the roll. A 4.2 m wide room on a 3.66 m roll needs a second drop and a join; the same room on a 4 m roll fits in one. The calculator flags this for you.
- What is the standard carpet roll width in Australia?
- Residential broadloom is mostly 3.66 m (12 ft), with 4 m common on newer ranges and 5 m on some commercial products. Pick the width that matches your supplier’s roll before reading the metres.
- How much wastage should I allow for broadloom carpet?
- About 10% for plain broadloom in a single room; more for patterned carpet that has to match across drops. Wider rooms relative to the roll produce bigger offcuts and higher wastage.
- How do I convert carpet square metres to linear metres?
- Divide the floor area by the roll width: 20 m² off a 3.66 m roll is 20 ÷ 3.66 = 5.5 linear metres before wastage. The m² ↔ linear metres converter does this either direction.