Fabric consumption calculator

The formula

For a knitted garment, consumption is the area of fabric the panels occupy, multiplied by the weight of the fabric. Mills across the industry use the same arithmetic:

(Body length + sleeve length + allowance) × ((chest width × 2) + allowance) × gsm ÷ 10,000,000 = kg per piece

Chest width is a half measure taken flat, so doubling it gives the full circumference — which is the same thing as the front and back panels laid side by side. Dividing by ten million converts square centimetres × grams into kilograms. Wastage is then added on top.

Why the allowance matters more than you would think

The allowance covers everything the finished measurements do not: seam allowances, hem depth, neck rib, cuff and waistband ribs, pockets, plackets and hoods. A hoodie needs far more allowance than a tee — the hood alone is a significant piece of cloth — which is why the presets above set it differently for each garment.

Get the allowance wrong and every number downstream is wrong. If you are unsure, err high: under-ordering fabric mid-production is far more expensive than a small surplus.

What changes the real number

• The marker. How panels are nested on the fabric width decides real yield. A good marker on the right width can save several percent.
• Your size ratio. A ratio weighted to large sizes consumes more. Give the factory the real ratio before asking for a price.
• Fabric width. Tubular versus open width, and the finished width itself, change how efficiently panels nest.
• Direction. Pile fabrics like velour and corduroy must be cut one way, which removes some nesting freedom and raises consumption.

Once you have kilograms per piece, drop it straight into the garment costing calculator to see what it does to your price.