BCF Carpet Face Weight, Pile Yarn Consumption & Line Supply

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 7 inputs are read from the form on every keystroke: Tuft Density, Pile Height, Backing Allowance per Tuft, Tufted Yarn Count, BCF Line Output, Usable Yarn Yield and Yarn Price.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Face Weight together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Face Weight, Yarn per Tuft, Pile Yarn Length, Pile Density, Yarn Cost per Square Metre, Yarn per 100 m2, Usable Yarn from the Line, Lost to Waste, Carpet Supplied and Carpet Supplied per Day — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

The tool loads with this case already solved — the Face Weight shown above is its answer. Change one value and the difference from this baseline is the sensitivity of the result to that variable.

How to use it

1. Work through the input groups in order — Construction and Supply. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Face Weight in the dark results panel — that is the headline figure, expressed in g/m2.
4. Check the supporting rows underneath (Face Weight, Yarn per Tuft, Pile Yarn Length, Pile Density, Yarn Cost per Square Metre, Yarn per 100 m2, Usable Yarn from the Line, Lost to Waste, Carpet Supplied and Carpet Supplied per Day) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Face Weight before a trial is booked, so machine time and material in Carpet & Floor Coverings are committed against a calculated figure rather than an estimate.
• Costing and quotation — Face Weight is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Tuft Density) shows how much of the gap in Face Weight each variable explains.
• Teaching and study — the accepted ranges bracket normal Carpet & Floor Coverings practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Assumptions and limits

• Face weight here is pile yarn above the backing and nothing else: no primary backing, no latex, no secondary backing, so it is the figure a specification means by face weight rather than the total weight of the carpet, which is substantially higher. The yarn per tuft is twice the pile height plus a stated allowance, which is the geometry of a tuft that goes down and comes back up; real consumption runs a little above it because yarn is taken up over the needle and because pile height is measured after the carpet is finished rather than as it is tufted. Loop pile and cut pile take the same length for the same finished height, but a cut pile is measured to the tip of the cut yarn, so entering the same number for both understates the loop construction. Pile density is face weight over pile height and is the number that separates two carpets of equal face weight, one of which is dense and short and will wear, the other tall and sparse and will not. The line supply figure assumes the whole output goes to this construction at this count, which is a planning number rather than a schedule.
• Every input is bounded to the range normal practice occupies (Tuft Density 5000 to 500000 tufts/m2, Pile Height 1 to 40 mm and Backing Allowance per Tuft 0 to 10 mm, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Questions people ask