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Order on fabric length and you will run short. Crimp and waste are not optional.
Warp Yarn to Indent
—kg
Including crimp and waste allowances
Requirement Breakdown
Net Yarn in Fabric
—kg
Crimp Allowance
—kg
Waste Allowance
—kg
Warp Yarn per Metre of Fabric
—kg/m
Preparation waste covers creel tails, beam gaiting, knotting and the leftover on the beam. 2-4% is normal for a well-run shed.
Using this calculator
About the Warp Yarn Requirement Tool with Waste Factor
The formula
This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.
Net yarn in the fabrictex = 590.5 / yarnNe baseKg = ends x warpLength x tex / 1000000
Tex is grams per 1,000 metres, so ends x metres x tex is grams per 1,000 metres of thread — dividing by a million converts it to kilograms in one step. The English count has to become tex first because Ne is an inverse measure and will not multiply.
Allowances, applied in sequencewithCrimp = baseKg x (1 + crimp / 100) warpKg = withCrimp x (1 + waste / 100)
The order matters and the multiplication is deliberate. Waste is taken on the crimped weight, because what the preparation department loses is real yarn, not fabric-equivalent yarn.
Unit rate for costingkgPerMetre = warpKg / warpLength
The figure to carry into a cost sheet, since it survives a change of order quantity where the total does not.
Symbols used above
Symbol
Stands for
Unit
ends
Total warp threads across the full width, not per inch
no.
warpLength
Length of warp on the beam — the fabric length plus the crimp it will take up
m
Ne
English cotton count, hanks of 840 yards per pound
hanks/lb
tex
Linear density in grams per 1,000 metres — the direct system, which multiplies where Ne does not
g/km
crimp
The percentage by which warp is longer than the cloth it makes, because it waves over and under the weft
%
How the result is derived
Step by step, from the values you type to the figure on screen.
The English count is converted to tex, because Ne is an inverse measure — twice the Ne is half the yarn — and inverse measures cannot be multiplied through a weight calculation.
Ends, length and tex are multiplied to give the net weight of yarn that ends up in the cloth.
The crimp allowance is added, because warp does not lie straight: it waves over and under every pick, so more yarn goes in than cloth comes out.
The waste allowance is applied on top of the crimped weight, covering creel tails, beam gaiting, knotting and the unusable remainder left on the beam.
The two allowances are reported separately as well as combined, so a mill can see which one is driving the indent and audit each against its own records.
What each input means
Where to read each value on the floor, the unit it must be in, and the range the tool accepts.
Input
Unit
Accepted range
Default
What it means
Total Ends
no.
1 to 50000 no.
6000
Warp Length
m
10 to 500000 m
25000
Yarn Count
Ne
1 to 300 Ne
40
Warp Crimp
%
0 to 20 %
6
Preparation Waste
%
0 to 15 %
3
What the tool returns
The headline figure and every supporting value it is built from.
Output
Unit
What it tells you
Warp Yarn to Indent (headline result)
kg
Including crimp and waste allowances
Net Yarn in Fabric
kg
Crimp Allowance
kg
Waste Allowance
kg
Warp Yarn per Metre of Fabric
kg/m
Worked example
Given
Total ends
6,000
Warp length
25,000 m
Yarn count
40 Ne
Warp crimp
6%
Preparation waste
3%
Substituting
tex = 590.5 / 40 = 14.7625baseKg = 6000 x 25000 x 14.7625 / 1000000 = 2214.375withCrimp = 2214.375 x 1.06 = 2347.238 (crimp allowance 132.86)warpKg = 2347.238 x 1.03 = 2417.655 (waste allowance 70.42)kgPerMetre= 2417.655 / 25000 = 0.09671
Answer
Net yarn in fabric
2,214.38 kg
Crimp allowance
132.86 kg
Waste allowance
70.42 kg
Warp yarn to indent
2,417.65 kg
Warp yarn per metre
0.0967 kg/m
The allowances add 203.28 kg — 9.18% of the net, not the 9% a quick mental sum suggests, because 1.06 x 1.03 = 1.0918 rather than 1.09. On this order the difference is 4 kg and does not matter; on a 500-tonne annual contract the same compounding is four and a half tonnes, which does. Order 2,214 kg against the fabric weight and the warp runs out with 8% of the order unwoven.
How to use it
Work through the input groups in order — Warp Set and Allowances. The defaults are a realistic case, so you can change one value at a time and watch what moves.
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.
Read Warp Yarn to Indent in the dark results panel — that is the headline figure, expressed in kg.
Check the supporting rows underneath (Net Yarn in Fabric, Crimp Allowance, Waste Allowance and Warp Yarn per Metre of Fabric) before acting on the headline — they are where an implausible input usually shows itself first.
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
Raising the yarn indent for a confirmed order, which is the calculation this tool exists for.
Costing at quotation stage, where kilograms per metre is the number that goes into the sheet.
Auditing preparation waste — compare the waste percentage that reconciles against actual issue and return figures with the one assumed here.
Sizing a warping and sizing plan, since beam count follows from total warp weight and beam capacity.
Reading the result
Typical bands and what each one is telling you.
Value
What it indicates
Crimp 4 to 8%
Ordinary shirting and sheeting in plain weave. The default 6% is a reasonable starting assumption for a balanced construction.
Crimp 8 to 12%
Denser or unbalanced constructions, and heavier weft. Measure it rather than assume it — crimp is the larger of the two allowances and the one most often wrong.
Waste 2 to 4%
A well-run preparation department. The default 3% sits in the middle of it.
Waste above 6%
Worth investigating rather than budgeting for. Usually short warps, frequent set changes, or beam remnants nobody is measuring.
Assumptions and limits
One count across the whole warp. Striped, dobby and multi-count warps must be calculated per group of ends and summed — running the average count through this tool gives the wrong weight, because weight is linear in tex and tex is not linear in Ne.
Warp length is the length on the beam. If the figure to hand is fabric length, the crimp allowance converts it; entering fabric length and then also applying crimp is correct, entering beam length and applying crimp counts it twice.
The conversion constant 590.5 is the cotton Ne standard. Worsted, woollen and linen counts use different constants and must be converted first.
Size add-on is not included. This is the weight of yarn to buy, not the weight of the sized beam, which will be 8 to 15% heavier.
Standards and further reading
ISO 1144 — textiles, universal system for designating linear density (the tex system).
ASTM D1907 — linear density of yarn by the skein method, the reference for confirming a delivered count.
ISO 7211-3 — determination of crimp of yarn in woven fabric, the measurement behind the crimp allowance.
Questions people ask
Why convert to tex at all? Can this not be done in Ne?
Not directly, because Ne is an indirect count: a higher number means less yarn per unit length. Weight is proportional to linear density, so the arithmetic needs a direct system, and tex is the direct system. Skipping the conversion and multiplying by Ne inverts the whole result — a 40s warp would be reported as roughly seven times heavier than a 5.9s one instead of seven times lighter.
Should waste be calculated on the net weight or on the crimped weight?
On the crimped weight, which is what this tool does. The yarn a creel tail or a beam remnant loses is physical yarn that has already been paid for, not the fabric-equivalent portion of it. Taking both allowances on the net figure and adding them understates the indent by the product of the two — small at 6% and 3%, and no longer small at 12% and 8%.
My actual consumption keeps exceeding this figure. Where is it going?
Check crimp first, because it is the bigger allowance and the one usually assumed rather than measured. Denser weft or a heavier pick than the specification raises warp crimp directly, and a construction running 10% crimp against a 6% assumption is a 4% shortfall on its own. After that, look for beam remnants and set-change losses, which are real waste that a 3% figure may simply not cover.
