Fabric Consumption Calculator (woven and knit garments)

About the Fabric Consumption Calculator (woven and knit garments)

Work out how much fabric a garment takes before you sample it or quote for it. Enter the pattern pieces of the base size — each piece’s length, width and how many the garment has — with the seam and hem allowances, then the fabric: for a woven its cuttable width, for a knit its weight in grams per square metre (GSM). With the marker efficiency and the wastage, the calculator gives the fabric per garment in metres and yards, or for knits in grams and kilograms per dozen, the trade’s usual unit.

List the sizes with their ratio (1 : 2 : 2 : 1) and the order quantity: each size is graded from the base size, the order is split over the sizes in whole pieces, and the fabric for the whole order comes out in metres, yards and kilograms. An optional cost line turns the consumption, the fabric price (by the metre, yard or kilogram), trims, CMT and other costs into a cost per piece and an FOB price with your profit. Six garments to start from — a T-shirt, a hoodie, a shirt, trousers, a kurta and a dress — fill in example measurements to replace with your own. Without a pass the free preview shows the fabric per garment in full with the first rows of each table; the other figures, the copy, the CSV and printing need a Pro pass.

Common uses

• Costing a new style for a buyer’s FOB quote before the sample is made.
• Checking a supplier’s or a factory’s consumption figure for a T-shirt, a shirt or trousers.
• Working out how many kilograms of knit fabric to order for a size-wise order.
• Comparing a woven fabric of 112, 147 or 150 cm width for the same garment.

The formula: pattern area, marker efficiency and wastage

A quick consumption estimate adds up the area of the pattern pieces and divides it by the share of the fabric that a marker — the lay plan of the pieces on the fabric — turns into pieces:

• cut area = Σ (length + length allowance) × (width + width allowance) × pieces
• fabric area = cut area ÷ marker efficiency × (1 + wastage)
• woven: metres = fabric area ÷ cuttable width; yards = metres ÷ 0.9144
• knit: grams = fabric area × GSM; kilograms per dozen = grams × 12 ÷ 1,000

The pieces are measured as rectangles around each pattern piece (its longest length and widest width), and the marker efficiency accounts for the fabric lost between curved pieces.

Knit fabric: kilograms per dozen

Knit fabric is bought by weight, so its consumption is a weight: the fabric area times its GSM (grams per square metre). For a T-shirt the usual short form is (body length + sleeve length + allowance) × (half chest + allowance) × 2 × GSM × 12 ÷ 10,000,000 = kilograms per dozen, with lengths in centimetres; entering the body and sleeve as one piece of that size, two pieces, gives exactly the same result. To find the GSM of a fabric, weigh a 10 × 10 cm square (100 cm²) and multiply its grams by 100. A tubular knit holds two layers: each running metre of a tube with a 45 cm flat width is 0.9 m² of fabric, so tick Tubular to convert its weight to metres.

Marker efficiency and wastage

Marker efficiency is the area of the pattern pieces as a share of the fabric in the marker. Plain, boxy pieces nest well; curved, one-way or matched pieces leave more fabric between them. The garments to start from use 78–85% as starting values: check yours against a real marker from your cutting room or CAD system. Wastage covers what a marker does not: the ends of each lay, splices, fabric faults and cutting loss.

Sizes, grading and the size ratio

The pieces are measured on the base size. A size one step larger grows every piece by the length grade and the width grade (for example 2% and 4%), two steps by twice that, and a smaller size shrinks them; the seam and hem allowances stay the same in every size. The order is split over the sizes by their ratio in whole pieces that add up to the order — 1,200 pieces at 1 : 2 : 2 : 1 are 200, 400, 400 and 200 — with the pieces left over after rounding given to the sizes with the largest remainders.

From consumption to an FOB price

The cost line prices the fabric of the order’s average piece (or of the base size without an order) by the metre, yard or kilogram, then adds the trims, CMT (cut, make and trim) and other costs per piece: cost per piece = fabric + trims + CMT + other. The FOB price adds your profit to that cost: FOB = cost × (1 + profit). Freight, duty and the buyer’s landed cost are not in it; the Landed Cost Calculator adds them.

Units

Measurements may be typed in centimetres or inches. An inch is exactly 25.4 mm (NIST), so a yard of 36 inches is exactly 0.9144 m. Switching the units converts the pieces, the allowances and the width already typed.

Limitations

• An estimate from the pieces’ outer rectangles and a marker efficiency: a real marker from your cutting room or CAD system is the exact figure.
• Stripes, checks and one-way prints that need matching take more fabric than the area suggests: raise the wastage or lower the efficiency.
• Shrinkage is not added by itself: put it in the allowances or the wastage.
• Grading is a share of each piece per size step; a graded pattern set is more exact for unusual size ranges.
• Rib, collar and lining fabrics with their own price or weight are best worked out as a separate run of the calculator.

Privacy

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Your pattern pieces, sizes and prices are worked out in this browser and remembered on this device only; nothing is uploaded.