Like other business, apparel industry is going to be competitive marketplace. So, as a garment merchandiser we need to control manufacturing costs of a product. We need to minimize our manufacturing cost for getting more profit. As we know, sewing thread is one of the common accessories in the garment industry. By minimizing sewing thread consumption, we can save maximum wastage for an order. By saving sewing thread for a particular order or style, not only saving money, but also save warehouse maintenance cost. To estimate sewing thread consumption for an order, merchandise need to understand the stitching and way of cloth stitching.
Before going to bulk booking of sewing thread, garment merchandiser need to know the way of calculating sewing thread consumption per stitch machine wise and using best sewing machine for making clothes to minimize sewing thread wastage. Also need to calculate sewing thread consumption in one garment then go for bulk production. 
Thread consumption means how much thread we need to for making a cloth. To determine sewing thread consumption, there is a standard formula. By using a standard formula, you will get multiplied factors according to machine type and stitching classes. To estimate sewing thread consumption, you have to multiply seam length with the factors. A unit length of seam depends on the following factors for actual sewing thread consumption;
- Classes of stitch
- Stitches per inches (SPI)
- Fabric thickness of the seam
- Thread tension
- Sewing thread count
- Estimate consumed actual sewing thread in a specific length of seam
- Find out the thread consumption by using mathematical stitch formulas based on thickness (fabric) of the seam and SPI (stitches per inch)
- Calculate sewing thread consumption by using A&E thread consumption calculation spreadsheets
Thickness of the seam (fabric thickness): 0.075 inches
SPI (stitches per inch): 11
Length of the seam: 44 inches
Mathematical equation for consumption: C = 4 + 2ts
Where,
T = thickness
S = stitch per inch
So, the result is: C= 4 + 2ts
= 4 + 2 (0.075 x 11)
= 5.65
Here, 44-inch x 5.65 = 248.6 inch / seam
With 15% seam wastage, 248.6 inch/ seam x 1.15 = 285.89 inch per seam or 7.94 yards per seam.
Let’s find out the estimate thread consumption of machine wise for garments sewing;
| Machine | Thread per inch stitching for sewing |
|---|---|
| Plain Machine - Single needles | 2.75 inches |
| Plain Machine - Two needles | 5.5 inches |
| Over lock Machine - Three threads | 15 inches |
| Over lock Machine - Four threads | 18.75 inches or 20 inches |
| Over lock Machine - Five threads | 23 inches |
| Safety stitch | 20 inches |
| Flat lock stitch | 22 inches |
| Chain stitches - one needles | 12.5 inches |
| Chain stitches - two needles | 25 inches |
| Button Hole | 24 inches |
| Bar take machine | 26 inches |
By using above consumption based on machine, let’s take a look example for better understanding;
Suppose, we will estimate sewing thread consumption for kid’s basic T-shirt and T-shirt has used 94 inch four thread over lock stitching, flat lock 48 inches, two needle chain stitches 18 inches and plain machine one needle 30 inches.
Now, as per above information the sewing thread consumption of kid’s basic T-shirt is;
In meter: (94 x 4 thread O/L) + (48 x F/L) + (18 x 2 needles chain stitches) + (30 x one needle P/M)
= (94 x 18.75) + (48 x 22) + (18 x 25) + (30 x 2.75)
= 1762.5 + 1056 + 450 + 82.5
= 3351 inch
= 3351 inch / 39.37 = 85 meter (As we know, 1 meter = 39.37 inches)
= 85 meter + 15% wastage
= 98 meter / body
So, as per above information, we need sewing thread for basic kid’s T-shirt is 98 meters per garment to complete the cloth stitching.
As we already know the way to determine sewing thread consumption per garments. Now let’s find out the cost of consuming sewing thread per garments. Take a look below example for clear understanding;
Suppose, a spun polyester 40/2 color sewing thread cone price is $0.80 for 4000 meters. And our consumption of per garment is 98 meters. So, what will be the cost of sewing thread per garment?
The unit price of a cone / total meter x consumption of per body
= 0.80 / 4000 x 98
= $ 0.0196
So, as per above consumption per body sewing thread cost is 0.0196$. For sewing thread’s costing purpose, you can download attached excel format for quick costing.
We already know the way of determine sewing thread consumption and costing per garments. Now let’s find the way to book bulk sewing thread for an order.
Suppose, our bulk order quantity is 150,000 pcs for basic T-shirt style and our sewing thread consumption is 98 meters per body. If per cone sewing thread is 4000 meters, then what will be the bulk sewing thread consumption for 150,000 pcs garments?
Total order quantity x Sewing thread per body / Per cone sewing thread
= 150,000 x 98 / 4000
= 3675 cones
So, we need 3675 cones for completing sewing 150,000 pcs garments.
