Last Updated on June 9, 2026
Merchandising is a very tough profession that you can’t imagine. To provide the best performance in their profession merchandiser has to have keen knowledge on mathematics. It will help them to escalate in their professional life.
Today I will try to compile some mathematical calculations which may help you to continue Merchandising daily activities. Please find the following formulas for your reference.
CBM Calculation for Garments and Container Capacity
CBM: CBM means cubic meter. CBM of 1 carton box can be determined in the following ways.
If your carton dimensions are in cm, divide each dimension by 100 first before you multiply, and always use the outside carton size.
Total CBM = 1 Carton CBM X Total Carton
There are 3 types of container you may found for goods exportation.
- 20 feet Normal Container to hold 33.2 CBM goods.
- 40 feet Normal Container to hold 67.7 CBM goods.
- 40 feet High Container to hold 76.4 CBM goods.
These are standard internal-volume figures, according to Maersk container specifications, 2024.
The third one is the 40-foot high cube container in shipping terms.
In practice, the usable carton quantity can be lower because of carton size, palletizing, and the shipment weight limit.
Containers are usually rented in two ways
- FCL: Full Container Load
- LCL: Light Container Load
In shipping terms, LCL means Less than Container Load, not Light Container Load, and it is used when the shipment does not fill a full container.
Poly Bag Costing Formula
We can follow below formula to find out poly bag costing.
Suppose,
A LDPE poly bag having 28” length, 3” flap, 14” width, 140-gauge thickness with self-adhesive facility and if the cost of polymer is $.50 per lb. Polymer is the main ingredients to produce poly bag. Let’s find out the cost of 1 PC poly bag.
So, the weight of material = (28 + 3 x 14 x 140) / 3300
= 60760 / 3300
= 18.412 kg / 1000 pieces
Cost of Material = 18.412 kg x $.50 per lb
= 18.41 x $1.1 Kg (as we know 1 kg = 2.20462 lb, according to NIST, 2024)
= $20.253 / 1000 pieces
= $0.020 (cost of 1pc poly bag)
Cost of Adhesive tape= 28” x $.002
= $.056
So, final cost of 1-piece poly bag will be = (0.020+.056)
= $0.076
For current sourcing, ask the bag supplier for resin grade, gauge tolerance, and print coverage, because those three items change bag cost more than the base resin price.
Carton Consumption and Carton Costing
Many Senior merchandisers have been doing merchandising for 5/6 years but regret to say that they can’t do Carton Consumption & Cost properly. They have to depend on Supplier Consumption & Costing. This shows that the supplier is taking money as he wishes. You don’t even understand yourself. Please download a ready-made formula to get carton box costing quickly.
A basic carton costing sheet should separate board, print area, lamination, stitching or pasting, and transport loss so you can compare supplier quotations line by line.
Carton’s square meters and volume
Carton CBM is calculated as Length x Width x Height in meters.
For carton costing, board grade, print area, and the number of cartons should be checked together, because they all affect the final price.
Sewing Thread and Embroidery Consumption
As a merchandiser, you have to count sewing thread frequently to find out product costing. Please download a ready made formula to get sewing thread costing quickly. I have attached another formula to get embroidery costing quickly. 
A thread estimate is more reliable when you separate seam type, stitch type, and stitch density instead of using one average for the whole garment.
Embroidery thread should be counted by design size and stitch density, because dense motifs use far more thread than a simple logo.
Now you have to keep in mind that the color of your order is different according to the number of colors, you will find out by adding the total. I ask them to come out differently according to the color. Because we use different sewing threads according to the color, if we take it out at once, we can see that it is less than 1/2 due to the point.
For mixed-color styles, calculate each color thread separately and then add wastage for matching and machine handling.
Primary Consumption and Marker Consumption
Talking a lot about Primary Consumption. I thought I would give Polo Shirt Consumption but suddenly I thought let’s discuss regarding Marker Consumption. Marker Consumption always gives Consumption of 20 Pieces Garments. This is basically done in case of Confirm order. One thing has to keep in mind here. From 20 pieces of Consummation, we will find 12 pieces of Consumption.
Treat that 20-piece marker only as a trial benchmark, because the approved marker and shrinkage allowance will give the final booking number.
Marker Consumption:
Marker Length X Marker Width X GSM / 1550/1000 / Marker Consumption X DZN + 7%
This figure changes with marker efficiency, fabric width, shrinkage, and cutting wastage, so always recheck it with the approved marker before bulk booking.
From this way, it is only available to get estimate body consumption which is essential to find out cost. However, from Primary Consumption to Marker Consumption, Fabric is less. Accurate fabric consumption can be getting through marker consumption.
Packing List and Packing Method
4 types packing List are using in garments industry.
- Solid Color Solid Size.
- Solid Color Assort Size.
- Assort Color Assort Size.
- Assort Color Solid Size.
Assort color and assort size orders should always be cross-checked against the ratio sheet before carton packing, otherwise packing mistakes happen very quickly.
Most of the 2 types of packing are listed in the garment industry.
- Solid Color Solid Size
- Assort Color Assort Size
What type of folding or packaging method usually used for packing the goods?
= Flat-pack, Shirt fold, Roll pack, Hanging method etc.
Flat-pack is common for saving space, Shirt fold is common for display-ready tops, Roll pack is useful for some knit items, and Hanging method is usually used when buyers want less creasing.
Please be remembered that the buyer will fix which packing method they will use.
If the buyer does not mention the method, ask for the packing instruction before cutting the bulk order.
Things to mention in the packing list. He is as follows: –
(1) Buyer Name (2) Order No (3) PO No (4) Item (5) Fabrication & GSM (6) Inspection Date (7) Ex-Factory Date (8) CBM (9) Order Quantity (10) Shipped Quantity (11) Short / Extra Quantity (12) Quantity (13) Price / Piece (14) Shipped Garments value (15) Garments Qty in per carton (16) Gross Weight (17) Net weight (18) Carton measurement (19) ) Factory Name & Address (20) Shipping Mark (21) Side Mark (22) Color Name (23) Destination (24) Shipping Line (25) Ratio (26) Ship of Mood (27) Garment Department.
If the shipment has multiple colorways, the packing list should also show carton-wise color and size breakup, not only the total quantity.
A clean packing list also helps the forwarder calculate freight, insurance, and customs declaration without asking for repeated corrections.
Woven Pant Consumption Formula
For Consumption of Pant, you have to have a good idea about 4 parts.
- Body
- Back Pocket
- Side Pocket
- Belt Loop
Let’s find the following formula to get estimate consumption of a pant.
[{(Body Length * Body Thigh weight) * No of parts} + {(Back Pocket Length * Back Pocket weight) * No of parts X No of Pocket} + {(Bag Pocket Length * Bag Pocket weight) * No of parts * No of pocket} + {(Belt Loop Length * Belt Loop weight) * No of parts * 2} * 12] / Fabric width * 36
= yards
[Note: Allowance will be added. Side Pocket Fabric is usually different from Body Fabric.]
If waistband, fly facing, pocketing, or lining fabric comes from a different material, calculate each one separately instead of mixing it with the body fabric.
Always use the usable fabric width, not the nominal mill width, when you convert the result into yards.
Garment Measurement in CM and Inch
Measurement means to measure anything. Garments have to measure accurately to fit with the customers. In the language of garments industry, measuring clothes is called Measurement. Two types of measurement are used in the garments industry.
For buyer approval, always write the tolerance range beside the base measurement, not only the nominal size.
- CM Measurement
- Inch Measurement
★ Centimeter Measurement:
When we use centimeter to measure garments in the industry that time it calls centimeter measurement.
We know
10 mm = 1 cm
1 mm = 0.1 cm
2 mm = 0.2 cm
3 mm = 0.3 cm
4 mm = 0.4 cm
5 mm = 0.5 cm
6 mm = 0.6 cm
7 mm = 0.7 cm
8 mm = 0.8 cm
9 mm = 0.9 cm
These metric conversions follow the NIST metric tables, 2024.
1 inch = 2.54 cm
24 inches × 2.54 cm = 60.96 cm
60.96 cm: ÷ 2.54 cm: = 24 inches.
These inch to cm conversions follow NIST, 2024.
When we measure cm and mm together in the Centimeter Measurement method, we must express it in cm.
Many factories call these fractions eighths, so always follow the buyer’s measurement chart if the style uses 1/8 inch or 1/16 inch grading.
★ Inch Measurement:
When we use centimeter to measure garments in the industry that time it calls inch measurement.
We know
1 Yarn = 1/8 inches
2 Yarn = 1/4 inches
3 Yarn = 3/8 inches
4 Yarn = 1/2 inches
5 Yarn = 5/8 inches
6 Yarn = 3/4 inches
7 Yarn = 7/8 inches
8 Yarn = 1 inches
18 inches 2 yarn = 18 1/4 inches
44 inches 4 yarn = 44 1/2 inches
11 inches 3 yarns = 11 3/8 inches
Many factories call these fractions eighths, so always follow the buyer’s measurement chart if the style uses 1/8 inch or 1/16 inch grading.
To measure the button size in garments trend they have to use ligne.
Button size is usually written in ligne on trim cards, especially for shirt buttons, snaps, and rivets.
As we know, 1 ligne = 0.635 mm, and If the button die is 14 mm.
Button die (in mm)/0.635 = button ligne
14 mm/0.635 = 22 L
Button sizes are usually rounded to the nearest ligne in trim buying, so always send both mm and ligne in the trim sheet.
As we know,
- 12 Pieces = 1 Dozen,
- 12 Dozen = 1 Gross,
- 12 Gross = 1 G.G (1728 pieces)
G.G means great gross.
Knitted T-Shirt Fabric Consumption Formula
Before going to the consumption calculation, you have to identify the major parts of a knitted T-shirt. A knitted T-shirt consists of the following parts which have to count during consumption making-
Body parts (Front + Back)
Sleeve (Left + Right)
Armhole (Left + Right)
For knit T-shirts, always check the approved marker and shrinkage allowance before you freeze the final consumption.
The safest way to use these calculations is to confirm the buyer’s spec, approved marker, and packing instruction before bulk booking. A quick recheck at that stage saves fabric, freight, and rework later.
Frequently Asked Questions (FAQs)
Q1. How do you calculate CBM for carton box in garments?
Ans: Multiply the outside carton length, width, and height in meters to get the CBM of one carton. Then multiply that by the total carton quantity to get shipment CBM, and round it the way your forwarder asks for it.
Q2. What is the difference between FCL and LCL in shipping?
Ans: FCL means Full Container Load, where one shipment uses most or all of the container. LCL means Less than Container Load, where your cargo shares the container with other shipments and is usually booked by volume or weight.
Q3. How do you calculate fabric consumption for a knitted T-shirt?
Ans: Use the approved marker, fabric width, GSM, and shrinkage allowance, then convert the marker area into yardage. Always check body, sleeve, and armhole parts separately because marker efficiency changes the final figure.
Q4. What should be included in a garment packing list?
Ans: A garment packing list should show buyer name, order number, PO number, item, quantity, carton measurement, gross weight, net weight, CBM, and shipping mark. If the order has mixed colors or sizes, include carton-wise breakup so the forwarder and buyer can verify it quickly.
