Knit Fabric Consumption: The Math Behind the Buy

Fabric is typically 60 to 70 percent of a knit garment's material cost, and the quantity to buy is decided by an estimate made months before a meter is cut. Estimate high and the margin ships to the mill as surplus fabric; estimate low and the order stalls at cutting while an emergency dye batch is begged for. Consumption math deserves more respect than the single scribbled figure it usually gets.

The knit consumption chain

For knits the estimate runs through GSM: panel area per garment (from the measurement chart, plus seam and shrinkage allowances), times fabric weight in grams per square meter, times the pieces, divided into kilograms. The knit fabric consumption calculator walks the chain; the GSM converter handles buyers who specify in ounces per square yard. Two honesty rules bind the inputs. GSM is the finished, relaxed GSM, not the greige figure and not the machine setting; the difference after dyeing and compaction can be ten percent by itself. And the allowance stack (shrinkage, curl, side trim) must be stated per element, not blurred into one "process loss" number nobody can challenge.

The estimate meets the marker

The estimate's silent assumption is a utilization figure: how much of the fabric becomes garment versus gutter. That number is not chosen at the desk; it is decided later by marker efficiency on the actual width the mill delivers. Which exposes the width dependency: consumption per piece moves with usable width, and a mill delivering two centimeters under the assumed width has quietly raised your consumption on every marker. State the width assumption on the estimate, and check delivered width against it at the fabric width conversion level, roll by roll.

Close the loop or drift forever

The estimate earns trust only if actuals flow back: fabric issued versus garments cut, per style, compared to the estimate that bought the fabric. Run that comparison every style and the estimating standard tightens season by season; skip it and the same safety percentage gets added forever, unexamined. The comparison is also where estimate-versus-actual variance stops being a costing abstraction and becomes a purchasing correction with a date on it.