Guide · Carpet
Carpet lineal metres and roll width, explained
Carpet is measured in square metres but bought in lineal metres off a roll of fixed width. The difference between the two is where carpet quotes go wrong. This guide shows how to cut each room along the roll and price what you will actually buy.
Square metres versus lineal metres
A carpet roll has a fixed width. In Australia most broadloom carpet comes in 3.66 m rolls (12 feet), and some ranges come in 4 m. When you order carpet, the supplier cuts a length off the roll. That length is the lineal metre figure, and you pay for the full width of the roll along it.
So the carpet you buy for a room is:
Lineal metres × roll width = square metres bought
The square metres of the room itself only tell you the minimum. A 3.6 m wide bedroom on a 3.66 m roll wastes a thin strip. A 4.2 m wide bedroom on the same roll needs a second piece, and most of that second piece is offcut.
Drops, and why direction matters
Each piece cut from the roll is called a drop. For a rectangular room:
- Choose which way the roll runs across the room.
- Divide the room's width (the side across the roll) by the roll width, and round up. That is the number of drops.
- Multiply the number of drops by the room's length (the side along the roll). That is the lineal metres.
- Try it the other way round as well, and compare.
Here is a 4.2 m by 3.6 m bedroom on a 3.66 m roll, worked both ways:
| Roll runs along | Width across roll | Drops | Lineal metres | m² bought |
|---|---|---|---|---|
| The 4.2 m side | 3.6 m | 1 | 4.2 | 15.37 |
| The 3.6 m side | 4.2 m | 2 | 7.2 | 26.35 |
The room is 15.12 m² either way. One direction buys 15.37 m², the other buys 26.35 m². Getting the direction right on every room is the single biggest lever in a carpet quote.
Direction is not only about price. The pile should run the same way across a room, and ideally through doorways into the next room, so the colour looks even. Seams are best kept out of main walkways and should not run across strong light from a large window. An estimator who knows the installer's preferences will sometimes choose the dearer direction on purpose. That is a judgement call, and it should stay with the estimator.
A worked example: three bedrooms, a robe and a theatre
Example only
The room sizes, rate and naplock price are made up to show the method.
The selections put carpet in the bedrooms, the walk-in robe and the theatre. Robes in bedrooms 2 and 3 are included in the room sizes. On a 3.66 m roll, taking the cheaper direction for each room:
| Room | Size (m) | Net m² | Lineal m | m² bought |
|---|---|---|---|---|
| Bed 1 | 4.2 × 3.6 | 15.12 | 4.2 | 15.37 |
| Bed 2 incl. robe | 3.6 × 3.4 | 12.24 | 3.4 | 12.44 |
| Bed 3 incl. robe | 3.6 × 3.4 | 12.24 | 3.4 | 12.44 |
| Walk-in robe | 2.6 × 1.8 | 4.68 | 1.8 | 6.59 |
| Theatre | 3.6 × 3.6 | 12.96 | 3.6 | 13.18 |
| Total | 57.24 | 16.4 | 60.02 |
The order is 16.4 lineal metres, which is 60.02 m² of carpet for 57.24 m² of rooms. Priced at an example $55 per m² supply and install including underlay, that is $3,301.10. Add five naplocks at the doorways at $20 each and the carpet line comes to $3,401.10, or $3,402 rounded up to the dollar.
The walk-in robe is the least efficient cut: a 2.6 m wide piece taken from a 3.66 m roll leaves a strip about 1.06 m wide and 1.8 m long. An estimator who plans to use that strip elsewhere can shorten another room's order. That kind of saving depends on the installer, so it is worth agreeing as a rule rather than guessing on each quote.
When a room is wider than the roll
Rooms wider than 3.66 m need two drops, and the second drop is often mostly waste. Take a 5.0 m by 4.5 m lounge:
- Roll along the 5.0 m side: 4.5 m across needs 2 drops, so 10.0 lineal metres.
- Roll along the 4.5 m side: 5.0 m across needs 2 drops, so 9.0 lineal metres.
The better direction buys 9.0 × 3.66 = 32.94 m² for a 22.5 m² room. The second drop only needs 1.34 m of its 3.66 m width, leaving a strip about 2.3 m wide and 4.5 m long. Rooms like this are where offcut planning across the whole house pays off, and where a wider roll can change the answer.
3.66 m, 4 m and 5 m rolls
A wider roll is not always cheaper. The same five rooms above on a 4 m roll still need 16.4 lineal metres, because every room already fits in one drop. That buys 16.4 × 4 = 65.6 m², about 5.6 m² more than the 3.66 m roll. A wider roll pays off when it removes a seam: the 5.0 m by 4.5 m lounge fits a 5 m roll in a single 4.5 m drop, which is 22.5 m² bought for 22.5 m² of room and no join.
Check which widths the selected range actually comes in before choosing. Many ranges come in only one width.
Outside Australia
- UK and Ireland: carpet is usually sold per square metre, and 4 m and 5 m rolls are common. The lineal metre method is the same.
- US and Canada: carpet is usually sold by the square yard (9 sq ft, about 0.836 m²) off 12 ft or 15 ft rolls, and cut lengths are given in feet. Multiply the cut length in feet by the roll width in feet and divide by 9 to get square yards.
Extras on a carpet line
- Naplocks or carpet trims at every doorway where carpet meets another floor.
- Stairs, usually priced per staircase or per step rather than by area.
- Removal and preparation, such as pulling up old carpet or scraping up glued floor.
- Underlay, either in the rate or as its own line. Say which on the quote.
How Squaro works carpet
Squaro reads which rooms are carpet from the selections and measures each one from the plan's dimension strings. It then cuts each room along the roll in the direction that uses fewer lineal metres, at the roll width you set, and prices the area bought at your rate, with naplocks, staircases and scrape up from your rules. Each room shows its lineal metres and where on the plan it was read, and you can change any room's lineal metres if you are planning offcuts or seams differently. More on the carpet quoting software page.
Related reading
- Carpet quoting software that cuts along the rollReading carpeted rooms off the plans and pricing lineal metres off the roll.
- Flooring waste percentage, and when to round up to packsChoosing a waste figure, applying it in the right order, and rounding to whole packs.
- How to quote flooring from builder plansThe full method, from the builder's pack to a priced quote, with a worked hybrid example.
- The flooring quote checklist: what to check before you sendDocuments, scope, measurements, materials, trims, extras and wording, checked in a few minutes.
Quote your next plan set with Squaro
Squaro is open to a small group of flooring contractors first. Tell us how you quote and we will set up your rules with you and run your first plan.
Request early access