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Formula reference

Textile formulas

The formulas behind every Royal Style House calculator, written in plain words. GSM is sample weight in grams divided by sample area in square metres; GLM is GSM multiplied by the fabric width in metres; fabric consumption per garment is marker length divided by garments per marker, plus wastage. Each group below links to the calculator that does the arithmetic for you.

Checked against worked examples on 17 October 2026 · Royal Style House

Unit conversions used in textiles

QuantityFactorFormula
Length1 yard = 0.9144 mmetres = yards × 0.9144
Width1 inch = 2.54 cmcm = inches × 2.54
Weight1 kg = 2.20462 lblb = kg × 2.20462
Fabric weight1 oz/yd² ≈ 33.906 g/m²oz/yd² = GSM × 0.029494
Linear fabric weightGLM = grams per linear metreGLM = GSM × width (m)
Yarn: Ne ↔ TexNe is indirect, Tex is directTex = 590.5 ÷ Ne
Yarn: Ne ↔ Nmboth indirect countsNm = Ne × 1.6934
Yarn: Tex ↔ Denierboth direct countsDenier = Tex × 9

Fabric formulas

Fabric Consumption formula

A marker holds a fixed number of garments, so dividing the marker length by the garments in it gives the base consumption per garment. Cutting never uses 100% of the fabric, so a wastage percentage is added, followed by any extra allowance for shrinkage or shade variation. Multiply by the order quantity to get the fabric to book.

Base consumption
= Marker length ÷ Garments per marker
With wastage
= Base × (1 + Wastage% ÷ 100)
Final consumption
= With wastage × (1 + Allowance% ÷ 100)
Total fabric
= Final consumption × Order quantity
Yards
= Metres ÷ 0.9144
Weight (kg)
= Total m × Width (m) × GSM ÷ 1000
Fabric Consumption Calculator Learn it step by step

GSM formula

GSM is the weight of one square metre of fabric. Weigh a swatch of known size and scale the weight up to one square metre.

Sample area (m²)
= Length (m) × Width (m)
GSM
= Sample weight (g) ÷ Sample area (m²)
GSM cutter shortcut
= Weight of a 100 cm² disc × 100
oz/yd²
= GSM × 0.029494
GSM Calculator Learn it step by step

Fabric Cost formula

Mills quote by the kilogram but garments are costed by the metre. The calculator first works out how much one metre weighs (GLM = GSM × width), adds every per-kg cost, applies the supplier margin and wastage, and then converts the final per-kg price into per-metre and per-yard costs.

GLM (g per metre)
= GSM × Width (m)
Cost per kg
= (Price + Processing + Dyeing + Finishing + Other) × (1 + Margin%)
Wastage-adjusted / kg
= Cost per kg × (1 + Wastage%)
Cost per metre
= Wastage-adjusted / kg × GLM ÷ 1000
Cost per yard
= Cost per metre × 0.9144
Fabric Cost Calculator Learn it step by step

Fabric Weight formula

GSM tells you how many grams one square metre weighs. Multiply by the fabric area and divide by 1,000 to get kilograms.

Area
= Width (m) × Length (m)
Weight (kg)
= Area × GSM ÷ 1000
Total
= Weight per piece × Pieces
Pounds
= kg × 2.20462
Fabric Weight Calculator

GSM → GLM formula

GSM is weight per square metre; GLM is weight per running metre of the full width. Multiply GSM by the width in metres to convert.

GLM
= GSM × Width (m)
KG per metre
= GLM ÷ 1000
KG per 100 m
= KG per metre × 100
Total weight
= KG per metre × Length (m)
GSM → GLM Calculator Learn it step by step

GLM → GSM formula

Divide the weight of one running metre by the width in metres to get weight per square metre.

GSM
= GLM ÷ Width (m)
Metres per kg
= 1000 ÷ GLM
GLM → GSM Calculator

Fabric Width formula

All widths are converted through metres, then expressed in every unit. Subtracting the unusable edges gives the cuttable width for marker making.

cm
= inches × 2.54
inches
= cm ÷ 2.54
Cuttable width
= Full width − Selvedge (both sides)
Fabric Width Converter

Fabric Wastage formula

Whatever was issued but did not end up inside a garment is wastage. Compare it with what you costed to see if the cutting room is within budget.

Fabric used
= Garments × Consumption
Wastage
= Fabric issued − Fabric used
Wastage %
= Wastage ÷ Fabric issued × 100
Wastage cost
= Wastage × Price per metre
Fabric Wastage Calculator

Fabric Requirement formula

Start from the garments you will actually cut (order plus excess), multiply by net consumption, then add cutting wastage and shrinkage to get the gross fabric to book.

Garments to cut
= Order qty × (1 + Excess%)
Net fabric
= Garments to cut × Consumption
Fabric to book
= Net × (1 + Wastage%) × (1 + Shrinkage%)
Weight
= Metres × Width (m) × GSM ÷ 1000
Fabric Requirement Calculator

Fabric Roll formula

Rolls come in whole numbers, so the requirement is divided by the average roll length and rounded up.

Rolls
= ⌈ Fabric required ÷ Roll length ⌉
Roll weight
= Roll length × Width (m) × GSM ÷ 1000
Fabric Roll Calculator

Garment Costing formulas

Garment Costing formula

Every cost is converted to a per-piece figure. Direct costs are summed, factory overhead is added as a percentage, and profit is added on total manufacturing cost. Because buying-house commission is normally a percentage of the final FOB price, the price is grossed up so that the commission is fully covered.

Fabric / piece
= Fabric cost × Consumption × (1 + Wastage%)
Direct cost
= Fabric + Trims + Processing + Manufacturing + Packaging + Testing + Inspection + Transport
Overhead
= Direct cost × Overhead%
Total manufacturing cost
= Direct cost + Overhead
Profit
= Total manufacturing cost × Profit%
FOB price
= (Total cost + Profit) ÷ (1 − Commission%)
Commission
= FOB × Commission%
Order value
= FOB × Order quantity
Garment Costing Calculator Learn it step by step

CMT formula

A sewing line sells minutes. Cost per minute comes from labour cost; dividing by efficiency gives the real cost of each standard minute produced. Multiply by the garment's SMV and add overhead and margin to get CMT.

Cost per minute (CPM)
= Operator cost per hour ÷ 60
Effective CPM
= CPM ÷ Efficiency%
Labour / piece
= SMV × Effective CPM
CMT
= Labour × (1 + Overhead%) × (1 + Margin%)
Required operators
= Target × SMV ÷ (Hours × 60 × Efficiency%)
CMT Calculator Learn it step by step

FOB Price formula

Overhead and profit are added on cost, and the result is grossed up so that commission calculated on the FOB price is fully covered.

Cost
= (Fabric + Trims + CM + Other) × (1 + Overhead%)
FOB
= Cost × (1 + Profit%) ÷ (1 − Commission%)
FOB Price Calculator

Trims Cost formula

Each trim is priced per garment, thread is apportioned from the cone price, and a wastage allowance covers shortages and rejects.

Item cost
= Quantity per garment × Rate
Thread cost
= Thread m ÷ Cone length × Cone price
Trims / piece
= Σ item costs × (1 + Wastage%)
Trims Cost Calculator Learn it step by step

Garment Margin formula

A margin is a share of the selling price, so the cost must be divided by (1 − margin) — not multiplied by (1 + margin).

Selling price
= Cost ÷ (1 − Margin%)
Markup
= (Price − Cost) ÷ Cost × 100
Garment Margin Calculator Learn it step by step

Garment Profit formula

Margin is profit relative to price; markup is profit relative to cost. Both describe the same profit from different bases.

Profit
= Selling price − Cost
Margin %
= Profit ÷ Selling price × 100
Markup %
= Profit ÷ Cost × 100
Garment Profit Calculator

Packaging Cost formula

Per-piece items are summed directly; carton costs are divided by the carton's packing ratio.

Carton / piece
= (Carton + Tape) ÷ Pieces per carton
Packaging / piece
= Polybag + Hanger + Tissue + Stickers + Carton share
Cartons
= ⌈ Quantity ÷ Pieces per carton ⌉
Packaging Cost Calculator

Embroidery Cost formula

The stitch count drives machine time, so cost scales with stitches. One-time digitizing is spread across the order.

Stitching
= Stitches ÷ 1000 × Rate × Positions
Per piece
= Stitching + Applique + Digitizing ÷ Quantity
Embroidery Cost Calculator

Washing Cost formula

Weight × rate gives the basic wash; chemicals and manual effects are added, and rejects are loaded on top.

Wash / piece
= Garment weight (kg) × (Rate + Chemicals)
Total / piece
= (Wash + Special process) × (1 + Reject%)
Washing Cost Calculator

Production formulas

Marker Efficiency formula

Efficiency compares the area of fabric actually used by pattern pieces with the full rectangle of fabric the marker occupies.

Marker area
= Marker length × Marker width
Marker efficiency
= Pattern area ÷ Marker area × 100
Waste %
= 100 − Efficiency
Consumption
= Marker length ÷ Garments
Marker Efficiency Calculator Learn it step by step

SMV formula

Observed time is normalised to a standard pace with the rating, then allowances are added for rest and unavoidable delays.

Basic time
= Observed time × Rating%
SMV
= Basic time × (1 + Allowance%)
Output / hr
= 60 ÷ SMV × Efficiency%
SMV Calculator Learn it step by step

Line Efficiency formula

Efficiency is the share of paid minutes that turned into standard minutes of output.

Produced minutes
= Output × SMV
Available minutes
= Operators × Hours × 60
Efficiency
= Produced ÷ Available × 100
Line Efficiency Calculator Learn it step by step

Cutting Wastage formula

Anything issued that is not inside the marker — end loss, splices and remnants — is cutting wastage.

Fabric in markers
= Lay length × Plies
End loss
= End loss per ply × Plies
Cutting wastage %
= (Issued − Fabric in markers) ÷ Issued × 100
Actual consumption
= Issued ÷ Garments cut
Cutting Wastage Calculator

Production Capacity formula

Available minutes × efficiency gives productive minutes; divide by SMV to get pieces.

Hourly capacity
= Operators × 60 × Efficiency% ÷ SMV
Daily
= Hourly × Working hours
Weekly
= Daily × Days per week
Monthly
= Daily × Days per month
Production Capacity Calculator Learn it step by step

Daily Production formula

Calculate each line's daily output and divide the order quantity by the combined output.

Hourly / line
= Operators × 60 × Efficiency% ÷ SMV
Daily / line
= Hourly × Hours
Days
= Order qty ÷ (Daily / line × Lines)
Daily Production Calculator

Manpower formula

Required standard minutes divided by productive minutes per operator gives the operator count, adjusted for expected absence.

Operators
= Target × SMV ÷ (Hours × 60 × Efficiency%)
With absenteeism
= Operators ÷ (1 − Absenteeism%)
Helpers
= Operators × Helper ratio
Manpower Calculator

Machine Requirement formula

Each machine type must deliver its share of the garment's minutes every hour.

Hourly target
= Daily target ÷ Hours
Machines (type)
= Hourly target × SMV(type) ÷ (60 × Efficiency%)
Spare
= Working machines × Spare%
Machine Requirement Calculator

Yarn formulas

Yarn Count formula

Every system is converted to Tex (grams per 1,000 m) and then into all other systems. Direct systems rise with thickness; indirect systems fall.

Tex
= 590.5 ÷ Ne = 1000 ÷ Nm = Denier ÷ 9
Ne
= 590.5 ÷ Tex = Nm × 0.5905
Nm
= 1000 ÷ Tex = Ne × 1.6934
Denier
= Tex × 9 = 5315 ÷ Ne
dtex
= Tex × 10
Yarn Count Converter Learn it step by step

Yarn Consumption formula

Process and knitting losses are a share of the input, so each stage is divided by (1 − loss) rather than multiplied by (1 + loss).

Finished fabric
= Qty × Weight × (1 + Cutting%)
Greige fabric
= Finished ÷ (1 − Process loss%)
Yarn
= Greige ÷ (1 − Knitting loss%)
Yarn Consumption Calculator Learn it step by step

Yarn Cost formula

Freight and non-recoverable tax are added to the yarn value; dividing by usable kg shows what each kg in fabric really costs.

Purchase cost
= Price × kg + Freight × kg + Tax% × Yarn value
Landed / kg
= Purchase cost ÷ kg
Effective / kg
= Purchase cost ÷ (kg × (1 − Wastage%))
Yarn Cost Calculator

Ne ↔ Nm formula

Both are indirect systems: Ne counts 840-yard hanks per pound; Nm counts kilometres per kilogram.

Nm
= Ne × 1.6934
Ne
= Nm × 0.5905
Ne ↔ Nm Converter

Tex formula

Tex is grams per 1,000 metres; dtex per 10,000 m; Denier per 9,000 m.

dtex
= Tex × 10
ktex
= Tex ÷ 1000
Denier
= Tex × 9
Tex Converter

Denier formula

Denier is grams per 9,000 m. Dividing by filaments gives the fineness of each filament.

Tex
= Denier ÷ 9
Ne
= 5315 ÷ Denier
DPF
= Denier ÷ Filaments
Denier Converter

Export formulas

Commission formula

If commission must be paid out of the buyer's price, the net price is grossed up so you still receive your full net.

Included
= Commission = Price × Rate
Added on top
= Gross price = Net ÷ (1 − Rate)
Commission Calculator

FOB formula

Profit is added to product cost, inland transport and documentation are added to reach the port, and the price is grossed up for commission to give FOB. Freight gives CFR, insurance gives CIF, and the buyer's duty and charges give landed cost. Every figure is also shown in the buyer's currency at your exchange rate.

FOB
= (Product cost × (1 + Profit%) + Inland + Docs/pc) ÷ (1 − Commission%)
EXW
= FOB − Inland − Docs/pc
CFR
= FOB + Freight
Insurance
= CFR × (1 + Uplift%) × Insurance rate
CIF
= CFR + Insurance
Landed
= CIF + CIF × Duty% + Destination charges
Buyer currency
= Price ÷ Exchange rate
FOB Calculator Learn it step by step

FOB → CIF formula

Freight is spread across the shipment and insurance is calculated on the insured value.

CFR
= FOB + Freight ÷ Quantity
Insurance
= CFR × (1 + Uplift%) × Rate
CIF
= CFR + Insurance
FOB → CIF Calculator

Freight Cost formula

Sea freight is charged on volume; air freight on the higher of actual and volumetric weight.

CBM
= L × W × H (cm) ÷ 1,000,000 × Cartons
Volumetric kg
= L × W × H ÷ Divisor × Cartons
Sea freight
= CBM × Rate
Air freight
= max(Actual kg, Volumetric kg) × Rate
Freight Cost Calculator Learn it step by step

Export Margin formula

Convert the export price at your rate, add incentives, deduct bank charges and compare with cost.

Realisation
= Export price × Exchange rate
Net
= Realisation + Incentive − Bank charges
Margin
= Net − Cost
Break-even price
= Cost ÷ (1 + Incentive% − Bank%) ÷ Rate
Export Margin Calculator

Duty formula

Duty is charged on assessable value, surcharge on duty, and import tax on the duty-inclusive value.

Basic duty
= Assessable value × BCD%
Surcharge
= Basic duty × Surcharge%
Tax
= (Assessable + Duty + Surcharge) × Tax%
Duty Calculator

Landed Cost formula

Build up from FOB to CIF, apply duty and tax, then add local charges and divide by quantity.

CIF
= FOB + Freight + Insurance
Duty
= CIF × Duty%
Tax
= (CIF + Duty) × Tax%
Landed
= CIF + Duty + Tax + Local charges
Landed Cost Calculator

Currency Conversion formula

Multiply by your rate, then deduct any conversion or bank charges.

Converted
= Amount × Rate
Net
= Converted × (1 − Charges%)
Currency Conversion

Export Order Profit formula

Revenue is converted at your rate; costs are built from per-piece and order-level items.

Revenue
= Qty × Price × Rate
Cost
= Direct × (1 + OH%) + Commission + Bank + Freight
Profit
= Revenue + Incentives − Cost
Export Order Profit Calculator Learn it step by step

These formulas give exact arithmetic for the numbers you enter. Real fabric and production vary (shrinkage, wastage, GSM tolerance, efficiency), so use the results as planning estimates and confirm them against your own samples and lab reports.