CalculationTime
Precisely right, not estimated

Professional Flooring Calculator

Works the way flooring professionals do. Roll goods calculated from actual roll width and lay direction, not m². Carpet and vinyl pattern repeats matched exactly: straight match and half drop. Plank flooring laid row by row with real starters and enders, and tiles counted course by course.

1 Material & roll details
Roll goods (carpet and sheet vinyl) are sold by the linear metre from a roll of fixed width. The roll width determines how many drops are needed, not the square metreage.
Flooring type
2 Pile / construction type
The pile type determines how seams must be made, whether rib cutting is possible, and how forgiving the join will be. This is critical for professional seam planning.
Carpet / material construction
Loop pile selected (Berber, commercial loop, flatweave). Running/side joins can be made virtually invisible using the rib cutting technique: trimming along a rib channel cuts only the backing, not any fibre. Cross joins should be avoided entirely. All drops must run in the same direction (machine direction). Pattern repeats on loop pile are typically consistent and predictable.
3 Room dimensions
Measure the longest dimension as the length. Width is the shorter or the direction the roll will be cut across.
m
m
mm
Standard trim is 50 mm each end (100 mm total per drop). Increase to 75–100 mm for out-of-square rooms or large skirtings.
4 Lay direction
This is the direction the carpet runs from the roll: pile direction for carpet, or grain direction for vinyl. It determines the number and length of drops. Critically affects total linear metres and seam positions.
Running direction
Drops run parallel to the length of the room. Roll is cut to room length. Number of drops = room width ÷ roll width (rounded up). Seams run lengthways.
5 Pattern matching
Pattern matching is the most critical and most frequently miscalculated part of roll goods estimation. Select the type that applies to your material.
Professional knowledge
Direction: this is not optional, it is absolute
No piece of carpet can be placed running in a different direction to any other piece in the same installation. This is not merely about seam visibility. The colour of the carpet changes when light hits a differently-oriented piece: even from the same roll, cut from the same batch, the piece laid in the opposite direction will appear a noticeably different shade. This is a fundamental optical property of how pile reflects light, and it applies to every carpet type: cut pile, loop pile, twist, plush, Axminster, Berber, without exception.

The pile direction is the machine direction of the roll (the direction the carpet was manufactured, which is also the length of the roll). All drops and all cut pieces must run in this same direction. If a layout cannot be achieved with all pieces running the same way, the carpet cannot be laid properly from that roll: a different layout or different room configuration must be used.
Cross joins in doorways: sometimes unavoidable
The standard rule is to avoid cross joins, but a top-level professional will tell you they cannot always be avoided, particularly in doorways. Several physical realities make this the case:

Roll size and weight: A full 12 ft (3.66 m) width of carpet, depending on the pile weight and backing, can be extremely heavy and unwieldy. Getting a full-width roll through a standard interior doorway (typically 820–870 mm) is not always physically possible without damaging the carpet or scratching paintwork on the door frame. This is a real, practical constraint, not a failure of planning.

Doorway cross join technique: A top professional company will take accurate physical measurements of the entire floor plan and plan the cut layout on the cutting room floor before any carpet is put down. This allows them to plan drops where part of the roll runs through a doorway: the cut section from one room's drop generally drops into the opposite side, meaning the offcut from one room naturally becomes the piece needed for the adjacent room or hallway on the other side of the doorway. This minimises waste and keeps cross joins to their most defensible positions.

Cross join position matters: Where a cross join cannot be avoided, it should be placed in the doorway itself, specifically under the door where the door cover strip will conceal the join entirely. A cross join hidden under a door strip is invisible. A cross join in the middle of a visible floor is unacceptable.
Cross join rules by pile type: not all carpet is equal
Twist pile and plush pile (cut pile): Cross joins are less of a problem. The cut pile lies in a consistent direction and a well-made cross join with a seaming iron and tape can produce an acceptable result, particularly if the joint falls under a door strip or in a low-visibility position. Not ideal, but professionally acceptable when unavoidable.

Loop pile (Berber, commercial loop, structured loop): Avoid cross joins wherever physically possible. The loop structure creates a more visible edge at any cut, and the rib pattern of a loop carpet makes a cross join significantly more visible than a running join. However, as noted above, physical constraints in doorways may make a cross join unavoidable. When it cannot be avoided, a cross join on loop pile should be positioned under a door cover strip without exception.

Woven carpet, Axminster and Wilton: Apply the strictest standard. Axminster and Wilton are woven rather than tufted, meaning the pattern is integral to the weave. A cross join on a woven carpet disrupts the weave pattern, the pile direction, and the surface texture simultaneously. Avoid with every planning option available. When a cross join on a woven carpet truly cannot be avoided, it should be placed where it will never be seen: under a fixed piece of furniture, under a door strip, or in a concealed alcove.
The cutting room floor: professional layout planning
A top-level professional carpet company does not plan the cut layout in their head or on paper alone. They physically mark out the floor plan on the cutting room floor using chalk lines, then unroll the carpet over the plan. This allows them to:

• See exactly how drops fall relative to room dimensions and doorways
• Plan which offcut pieces from one drop fill adjacent areas without cross joins
• Identify where doorway cross joins are genuinely unavoidable vs where a different layout avoids them
• Confirm pattern repeat alignment before any cut is made
• Check that all pieces are running in the same pile direction before commitment

The cutting room floor is where the calculation becomes a physical plan. The numbers in this calculator give you the quantity and layout; the cutting room is where you validate it against reality.
Rib cutting on loop pile: the invisible seam technique
Loop pile carpets (Berber, commercial loop, flatweave, structured loop) are woven with a clear rib structure running along the length of the roll (the machine/pile direction). The selvage edge of the roll can be trimmed precisely by cutting down a rib channel.

How it is done: Identify a rib running parallel to the edge. Place a straight edge along the rib. Using a carpet knife or row cutter, cut firmly along the rib channel: you are cutting only through the backing (hessian, latex, or secondary backing). No carpet fibre is cut.

The result is a perfectly clean edge where the last complete row of loops terminates with uncut loops. When this edge is butted against the trimmed edge of the adjacent drop (also rib-cut), the loops from both pieces align rib-to-rib with no visible gap, no exposed cut fibre, and no fraying risk. The seaming tape bonds to two clean backing edges.

This technique applies only to running joins (side joins), not to cross joins, where the edges are cut ends and no rib structure is available.
Where should seams never be placed?
In open traffic areas mid-room: seams should be in the least visible, least trafficked position possible. At the top of stairs if carpet runs up them. Under furniture that moves: chairs being pulled out, table legs dragging. Perpendicular to natural light: seams running at right angles to a window create shadow lines. The exception: cross joins that cannot be avoided belong under door cover strips, not in the middle of the room.
Why calculate by linear metres instead of m²?
Because carpet is sold from a roll of fixed width (3.66 m). When you need more than one drop, you always take from the full roll width, even if you only use 400 mm of it. The waste on the wide strip is unavoidable. Only linear metres gives you the correct quantity to order. An m² calculation hides this entirely.
Linear metres from roll
10.20
lin. m required
Number of drops2
Roll width used3.660 m
Room area20.00 m²
Material required (area)37.33 m²
Pattern repeat waste0 m (free match)
True wastage %46.4%
Seam count1 seam (plan carefully)
Laying across the width saves 2.00 lin.m (8.20 vs 10.20 lin.m).
Narrow strip detected: two options
Last drop is only 0.340 m wide from a 3.660 m roll: 9% of roll width. A full second run wastes 3.320 m of roll width.

Option A (quality): Full second run = 10.20 lin.m. Running join, no cross join.
Option B (budget): Cross-join partial fill. Enter visible floor depth below.
Budget option: cross-join partial fill
m
Option B: Drop 1: 5.10 m + fill: 2.10 m = 7.20 lin.m total
Saving: 3.00 lin.m (29% less) vs full second run
Cross join at 2 m from the far wall: must fall under furniture.
Your offcut
Offcut from last drop: 3.32 m wide × 5.10 m long (16.93 m²)
→ Cut an area rug (have the edges bound or serged)
→ Or keep whole as a spare remnant for future repairs
Seam type analysis
Running joins: no cross joins for this rectangular layout

Seam positions from side wall:

  • Seam 1: 3.660 m from one side wall, 0.340 m from opposite wall

Check seam positions do not fall in a doorway or main traffic path.

Loop pile: rib cutting for running joins
Cut along a rib channel: through backing only, zero fibres cut. Butt rib-cut edges together and seam with carpet tape. Cross joins: avoid wherever possible; if unavoidable, position under a door cover strip. Direction is absolute.
Other direction: across the width
Drops: 2 · Total: 8.20 lin.m
Cut plan: drops from roll
Drop 13.660 m × 5.10 m
Cut from roll: 5.10 m (pos 0.00 m → 5.10 m)
Usable: 3.660 m wide × 5.10 m long (50 mm trim each end)
Drop 2 (partial)0.340 m × 5.10 m
Cut from roll: 5.10 m (pos 5.10 m → 10.20 m)
Usable: 0.340 m wide × 5.10 m long (50 mm trim each end)
Professional formula used
Drops = ⌈4.00 m ÷ 3.660 m⌉ = 2
Drop length = 5.00 m + 50 mm + 50 mm = 5.10 m
Total = 10.20 lin.m

Why this exists

Built by someone who laid the floors

I started laying floors in 1979 in my Dad's business in Brisbane: carpet and vinyl, cork tiles, parquetry, even synthetic turf on tennis courts. Later the flooring stores wanted me for measuring and planning. This calculator does the groundwork of every flooring quote: room area, the extra for waste, the pattern repeat on carpet and sheet vinyl, the starters and enders on planks, and an order rounded up to whole packs or roll lengths.

William Turner, founder

From the floor

Stains, soiling and what has changed

I'm showing my age, but I recall the shiny, static-filled nylons back in the day, and all of the dodgy marketing of the big companies.

Wool and its lanolin

Good old wool carpets did not need to be shampooed or steam cleaned as often as most of today's synthetics. Because of wool's natural oils, the lanolin, the dust would not stick, and so it did not get ground into the yarn, soiling the fibres. Most of the general dust that blows onto carpets today may not stick as much as when the static clung to it back in the day, but synthetics don't have lanolin. Sure, they have tried to match it, but I don't know if any synthetic has come close yet.

Hollow yarns and stain promises

I recall the Anso IV and Antron nylons back in the day: high-tech extruded yarn that was hollow, the hollow part trapping the light and making the synthetics less shiny. Then there were the big manufacturers talking up better stain resistance in synthetics. The Pro Hart Stainmaster ads: I wonder how many recall that load of bull. Crikey, I was amazed they could get away with advertising what they did, when the fine print of their fancy stain-free guarantees excluded tea and coffee straight up, or any hot liquids.

Floors that lay flat

We do have nicer floors these days in many areas. The early sheet vinyl shrank faster on the surface than the backing did, and it was rolling itself back up off the floors, even when stuck down with good adhesive. It was just the science of it. Dimensionally stable was the lesson learned from those days: today's floors naturally lay flat.

Preparation comes first

Floor preparation is always going to be the most important part, and my two sons are the masters when it comes to this. Self-levelling engineered top coats have been a real game changer, and higher levels of precision are known now. I recall hearing about parquetry flooring lifting up lounge suites because it expanded so much. There are very few, if any, lessons left to learn in flooring these days.

William Turner, founder

Questions

Questions people ask about ordering flooring

How much flooring should I order?

Measure the room, into every doorway, and multiply length by width. Add a waste allowance: for plank floors, area plus 10% is enough for most rooms. The row plan shows when it isn’t, and a couple of spare boards cover a faulty or damaged one.

Why is carpet ordered in linear metres, not square metres?

Carpet comes off a roll of fixed width, almost always 3.66 m. Every drop takes the full width of the roll even if the room only needs part of it, so the order is the length of roll you cut, and the square metres of carpet bought are more than the floor.

What is a pattern repeat?

On patterned sheet vinyl or carpet, it is the distance before the pattern comes round again, most often 915 mm (3 ft). Each drop is cut so the pattern lines up with the one beside it, which adds length to the order. Plain carpet and planks have no pattern repeat.

Why avoid cross joins in carpet?

A cross join runs across the roll. It is weaker than a running join and harder to make invisible, so lay the carpet with the joins running lengthways where you can, and keep any cross join under a doorway’s cover strip.

What are starters and enders?

The cut pieces at each end of a row of planks. Layers cut the starters for the first few rows to stagger the joints, and look ahead so no row ends on a sliver; if one would, the starter is cut shorter or a longer one is used.

Which way should the planks run?

One way often takes more boards than the other. Check which way the floor in the next room runs and ask the client before ordering; it may never have come up in the store.

Sources

Where the figures come from

Roll widths, board sizes and pack sizes come from the product in front of you: enter them from the label or the specification sheet. The flatness limit is the product's own; the figures in the slab check are the common ones.

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