How to Calculate Fabric Consumption

Why consumption is the number behind your price

When a factory quotes a knit garment, the calculation underneath is simple: fabric consumption in kilograms multiplied by fabric price per kilogram, plus trims, plus sewing cost, plus decoration, plus overhead and margin. Fabric is usually the largest single line in that sum, so a design change that adds fabric to every piece moves your price more than most negotiation ever will.

Knit fabrics are bought by weight, so consumption for tees, hoodies and joggers is expressed in kilograms per garment. Woven fabrics are bought by the metre, so shirts and trousers are quoted in metres per garment at a stated width. The two convert through the fabric's weight per running metre: GSM times usable width in metres, divided by 1,000.

The basic formula, and three terms to keep apart

Three numbers are easy to mix up. Pattern weight is the area of the pattern pieces times GSM: the fabric that ends up in the garment. Marker consumption is pattern weight divided by marker efficiency, because the pieces never cover the whole lay. Consumption with allowance is marker consumption plus a percentage added on top for selvedges, lay ends, faults and shade splits. When you compare your figure with a factory's, make sure you are comparing the same one of the three.

For a tee, a workable estimate of pattern area is: body length plus a few centimetres for seams and hem, times chest width plus allowance, doubled for front and back, plus the sleeves and the small pieces. Multiply square centimetres by GSM and divide by ten million to get kilograms.

The practical takeaway is proportionality: at the same pattern, consumption scales linearly with GSM, so a 240 GSM tee uses a third more fabric weight than a 180 GSM tee (240 ÷ 180 = 1.33). Size changes act on both length and width, so they grow area faster than either measurement alone.

Worked example: a size L t-shirt in 180 GSM jersey

A simplified illustration with stated assumptions, not a measured marker: a size L tee with 74 cm body length, 56 cm chest width and 22 cm sleeves, 4 cm added to each for seams and hem. Body panels: 78 × 60 × 2 = 9,360 sq cm. Sleeves, as two rectangles: 26 × 44 = 1,144 sq cm for the pair. Neck rib and bindings: about 400 sq cm, an assumption. Total pattern area: 10,904 sq cm, or 1.090 square metres.

Pattern weight at 180 GSM: 10,904 × 180 ÷ 10,000,000 = 0.196 kg. With an assumed marker efficiency of 80 percent, marker consumption is 0.196 ÷ 0.80 = 0.245 kg. With an assumed 10 percent allowance on top, consumption is 0.245 × 1.10 ≈ 0.270 kg per piece, 37 percent above the pattern weight.

In metres, at 180 cm usable width the fabric weighs 180 × 1.8 ÷ 1,000 = 0.324 kg per running metre, so 0.245 kg is 0.76 m and 0.270 kg is 0.83 m. For 300 pieces that is about 80.9 kg, 249.5 m, or 449.2 square metres of fabric bought. The calculator above starts from exactly these inputs; change any of them and the result follows.

The assumptions carry the result. With the same pattern, an 88 percent marker and an 8 percent allowance give 0.241 kg; a 75 percent marker and a 15 percent allowance give 0.301 kg. A wider chest grows it too: at 64 cm chest the body panels become 78 × 68 × 2 = 10,608 sq cm, 13 percent more than 9,360. This is why the only reliable consumption is the one taken from your own pattern and the factory's marker, or from a weighed sample.

Markers, lays and where the waste comes from

Factories do not cut garments one at a time. They make a marker: a cutting plan that nests the pattern pieces of multiple sizes across the full fabric width, then spread fabric in many layers and cut through the whole lay at once. Marker efficiency, the share of fabric area actually covered by pattern pieces, is commonly quoted at 75 to 88 percent for cut-and-sew knits depending on how well the shapes tessellate; your factory's own marker replaces that planning range.

The gaps between pieces are already inside marker consumption. What the allowance on top covers is the rest: edge losses at the selvedges and lay ends, fabric faults that must be cut around, shade splits between rolls, and shrinkage allowance if the fabric relaxes after spreading. Factories commonly quote 8 to 15 percent for knits, more for stripes and checks that need matching and for engineered or placement prints. Some factories quote one combined wastage figure instead; ask which one you are looking at.

• Marker gaps (inside marker consumption): 12-25% of the lay at 75-88% efficiency
• Selvedge and lay-end losses: part of the allowance
• Fault cut-outs and shade segregation: variable by fabric quality
• Stripe and check matching: a higher allowance than solids
• Placement and engineered prints: a higher allowance again

Getting a real consumption figure

This guide does not publish one consumption number per garment type, because the number depends on your pattern, size range, fit, GSM, usable width and the factory's marker, and a figure that ignores those is a guess. Three sources give a real one: the factory's marker for your graded pattern, stated as marker consumption and allowance separately; a cutting report from a sample or pilot run; or, as a check, a weighed finished sample, which shows the fabric in the garment (close to pattern weight, less seam trimmings) and therefore a floor under any quoted consumption.

Small pieces are not free: hoods, kangaroo pockets, cuffs and waistbands add pattern area and sewing operations, which is part of why a hoodie costs multiples of a tee. Add them to the pattern area rather than estimating a hoodie from a tee.

How to use consumption when negotiating price

Once you know the consumption, factory quotes become legible. Fabric cost per piece is consumption with allowance times your fabric price: in the worked example, 0.270 kg times your price per kilogram, or 0.83 m times your price per metre. With that number you can judge whether the rest of the quoted price is reasonable for sewing, trims and margin. When a quote looks high, asking which consumption figure was used is a far more productive question than asking for a discount, because it either reveals an error or teaches you what your design actually costs.

Consumption is also your lever for cost engineering. Shortening a body length by 2 cm across thousands of units, removing a chest pocket, switching a stripe to a solid, or accepting a slightly narrower fit each cut real kilograms. Conversely, be suspicious of a quote that undercuts everyone at the same GSM and fit: the easiest way to hit a magic price is to quietly shave GSM or shrink the pattern, and you will not see it until bulk arrives. Fixing composition, GSM with a tolerance, and the measurement chart in writing closes that door.

Wovens in brief: metres instead of kilograms

For woven garments, consumption is quoted in metres at a stated usable width. The same three terms apply: pattern area, marker consumption, and allowance on top, and the same drivers push metres up or down: bigger patterns, pattern matching and placement details up, better marker efficiency down.

Width matters in wovens in a way buyers sometimes miss: the same garment can need fewer running metres on wider fabric if the marker can use the extra width, so a price per metre only compares at the same width. To compare fabrics of different widths, convert to price per square metre: price per metre ÷ usable width in metres.