How to Calculate Fabric Consumption of a Garment?
The best way to calculate fabric consumption is to measure the pattern pieces that make up the garment and then calculate the total area of fabric needed. You then need to allow for seams, hems and other finishing details.
When you are starting a clothing line or you are managing a clothing production, you need to know how much fabric to buy. You need to allow for some wastage, as garments will not always be made to perfection and you will want to have some spare fabric in case of any mistakes. You also need to allow for design changes – you may start with one design but end up changing it part way through production.
Garment factories are businesses, and just like any other business, their goal is to generate profit. This can be done by minimizing costs in all aspects of production. In the garment industry, the fabric is the most important cost factor, representing around 60-70% of the total manufacturing cost. Fabric cost depends on how much fabric is used to make a garment, including cut waste and end bits. It’s important to calculate fabric consumption accurately.
Garment factories in India typically rely on pattern masters to determine fabric consumption. The rest of the employees do not usually bother how it is done. However, if you have a product technical sheet, you can calculate the exact fabric consumption of a garment. The average fabric consumption also depends on the nature of the fabric, like tubular or open width fabric. Whether the fabric is solid colored, check or stripe, or any specific design repeat required can also affect calculation. In the following, one example has been shown with a formula for better clarification.
Basic formula:
To estimate fabric consumption for a knitted top use the following formula.
Consumption in grams= {(L*C) + (B*SL)}*2*GSM/10000 grams
(when length units are in centimeter)
Where,
C= Chest +allowance
L= length of the body measure + allowance
SL= Sleeve length +Allowance
B=Biceps +allowance
GSM = fabric weight in grams per square meter
Example: Product – knitted top. Garments components are front, back, and sleeves.
Measurements without allowances
Measurement with allowances
Chest (C) = 23.25”
Body Length (L) = 30.5”
Sleeve Length (SL) = 26”
Bicep (B) = 9.2”
Fabric GSM =200
+1.75” = 25”
+2.50” = 33”
+1.50” = 27.5”
+0.80” = 10”
As per above formula consumption of fabric for this style is
= {(L*C) + (B*SL)}*2*GSM/10000 grams
= [{(33*25) + (10*2*27.5)}*2*(2.54*2.54)*200]/10000 grams (Note: 2.54 is inch to cm conversion factor)
= [{825+550}*400*6.45]/10000 grams
= 354.83 grams
Note: When you’re figuring out how much fabric to buy for a garment, keep in mind that you’ll lose some fabric width to the seams, and there will be some wastage as well. The amount of fabric you need overall will depend on the size of the garment and the weight of the fabric.