How to calculate fabric cost per T-shirt from the price per kg

Knitted fabric suppliers almost always quote in euros or lei per kilo, because circular-knit fabric is produced and weighed by the roll. Your customer, however, pays per garment. The link between the two is a single number: fabric consumption per garment, in kilos. Once you know it, the rest is a multiplication.

The basic formula

Fabric cost per T-shirt = consumption (kg per piece, including waste) × price per kg.

If one T-shirt uses 0.20 kg and the fabric costs a hypothetical €10 per kg, the fabric costs you €2.00 per shirt. The hard part is not the multiplication but the 0.20 kg. It depends on size, style, fabric weight, fabric width and how efficiently the pattern pieces are laid on the cutting table.

Method 1: from pattern area and GSM

If you have the patterns, you can estimate consumption without cutting anything:

1. Work out the area of each piece in square metres. For a classic size M T-shirt, let's assume a front of 0.37 m², a back of 0.37 m² and two sleeves of 0.10 m² each. Total: 0.94 m².
2. Multiply by the fabric weight. For a 170 g/m² single jersey: 0.94 × 170 = 160 g, or 0.16 kg net.
3. Divide by marker efficiency. Pieces never cover the fabric perfectly; there are gaps between them. At 80% efficiency, gross consumption becomes 0.16 ÷ 0.80 = 0.20 kg.

This is a good budget estimate, but not the final figure for your fabric order.

Method 2: from the real marker

The safest method is a marker made by the cutter or in CAD software on the actual fabric width. Lay out every size in the order, measure the marker length and calculate:

• marker weight = length (m) × width (m) × weight (kg/m²);
• consumption per piece = marker weight ÷ number of garments in the marker.

A hypothetical example: a 4.40 m marker on 1.80 m wide fabric at 170 g/m² weighs 4.40 × 1.80 × 0.17 = 1.35 kg and holds 7 T-shirts. Consumption is 1.35 ÷ 7 = 0.19 kg per piece. Then add end-of-lay and defect losses, usually a few per cent.

Method 3: weighing a sample

If you already have a sewn sample, weigh it without labels and trims. A finished T-shirt of 160 g does not mean 160 g of fabric bought, though: you must add the offcuts left on the cutting table, which you cannot see in the garment. Divide the weight by your estimated efficiency, as in method 1.

Where beginners usually go wrong

• They use the weight on the quote, but real fabric has a tolerance. A 170 g jersey may weigh slightly more or less; check the lot sheet.
• They calculate size M only. An XXL uses noticeably more, and your average cost depends on the size ratio.
• They forget width. The same pattern on narrower fabric can give a poorer marker and higher consumption.
• They forget shrinkage. If patterns are enlarged to allow for shrinkage in washing, consumption rises too.
• They compare suppliers on price per kilo alone. A fabric that is cheaper per kilo but heavier per square metre can produce a more expensive T-shirt.

A complete worked example with hypothetical numbers

Let's assume an order of 400 T-shirts, average consumption 0.20 kg, plus 3% for end losses and defects. Fabric needed: 400 × 0.20 × 1.03 = 82.4 kg, rounded to the rolls available. At a hypothetical €10 per kg, the fabric costs about €824, or €2.06 per T-shirt. That figure goes straight onto the first line of your cost sheet, and every other cost builds on it.

These numbers fit a 170 g red single jersey in 100% combed cotton very well: a classic weight for summer and promotional T-shirts that cuts cleanly and holds a print. It is in stock, so you can buy it by the roll with no minimum and cut a test marker before committing to the main order. You can see the weights available on the stock list, and for other shades browse the full single jersey range.

The figures in the examples are hypothetical and only illustrate the calculation. They are not Alteks Tricot prices: we quote the price per kg of each article on request, usually the same working day. Ask for a quote →