Fabric is the largest single cost in a knit garment, usually 55 to 70 percent of the FOB price. This t-shirt fabric consumption calculator gives you kilograms per dozen from body length, chest, sleeve and GSM, and the formula behind it is explained below.
T-Shirt Fabric Consumption Calculator
Enter your size-wise measurements and order quantity. Results update on Calculate.
| Size | Body length cm | Half chest cm | Sleeve cm | Qty (pcs) |
|---|
The fabric consumption formula for a t-shirt
Consumption is calculated from four measurements and the fabric weight:
Consumption (kg/dozen) = [(Body length + Sleeve length + Allowance) × (Half chest + Allowance) × 2 × GSM × 12] ÷ 10,000,000
What each term means:
- Body length — high point shoulder to hem, in centimetres, taken from the finished measurement chart
- Sleeve length — shoulder point to sleeve opening
- Half chest — one inch below the armhole, measured flat across
- Allowance — sewing allowance, cutting tolerance and shrinkage margin combined
- × 2 — front and back panels
- × 12 — converts one piece to a dozen
- ÷ 10,000,000 — converts square centimetres and grams per square metre into kilograms
The divisor is where people get stuck. One square centimetre of 180 GSM fabric weighs 0.018 grams. Dividing by ten million handles the centimetre-to-metre conversion and the gram-to-kilogram conversion in a single step.
A worked example
A men's basic crew neck in size L: body length 72 cm, half chest 52 cm, sleeve length 20 cm, fabric 180 GSM single jersey. Length allowance 10 cm, chest allowance 3 cm.
(72 + 20 + 10) × (52 + 3) × 2 × 180 × 12 ÷ 10,000,000
= 102 × 55 × 2 × 180 × 12 ÷ 10,000,000
= 2.42 kg per dozen
At 12 percent wastage that becomes 2.71 kg per dozen, or 0.226 kg per piece. A 12,000-piece order needs roughly 2,712 kg of fabric.
Choosing the right allowance
Allowance is where estimates usually go wrong, and it is not a fixed number. Sewing allowance depends on seam construction — a four-thread overlock side seam consumes more than a three-thread. Cutting tolerance depends on marker quality and how disciplined the cutting room is. Shrinkage depends on the fabric and whether it has been compacted properly.
For knit t-shirts in Bangladesh, 8 to 12 cm on length and 2 to 4 cm on chest covers most cases. Combed cotton behaves more predictably than carded. If residual shrinkage is high, or the buyer's measurement tolerance is tight, push the length allowance toward 12.
Wastage rates
The formula gives net consumption. What you book has to include wastage:
| Source of loss | Typical range |
|---|---|
| Cutting waste and end bits | 3–5% |
| Rejection and sewing defects | 2–4% |
| Fabric faults from the mill | 2–3% |
| Process loss in printing or embroidery | 1–3% |
Most factories book at 10 to 15 percent in total. Below 8 percent you will run short. Above 18 percent you are either hiding a real problem on the floor or giving away margin to the fabric supplier.
Consumption by size and GSM
If you need a quick figure without running the calculator, these are consumption values per dozen for a standard men's crew neck, including 12 percent wastage.
| Size | 160 GSM | 180 GSM | 200 GSM | 220 GSM |
|---|---|---|---|---|
| S | 1.96 | 2.20 | 2.45 | 2.69 |
| M | 2.13 | 2.40 | 2.67 | 2.93 |
| L | 2.32 | 2.61 | 2.90 | 3.19 |
| XL | 2.51 | 2.82 | 3.13 | 3.45 |
| XXL | 2.70 | 3.04 | 3.38 | 3.72 |
Figures in kilograms per dozen. Consumption scales linearly with GSM, so a fabric 10 percent heavier consumes 10 percent more weight for the same garment.
Tubular against open width fabric
Single jersey arrives either tubular or open width, and the choice changes what your consumption figure means in practice.
With tubular fabric, the body panel width is fixed by the tube diameter. If half chest plus allowance comes to 55 cm, you need a tube that opens to at least 55 cm flat. A wider tube than the garment needs means the excess is cut away on every piece and cannot be recovered, so the effective consumption rises above what the formula predicts even though the garment itself has not changed.
Open width fabric lets the marker maker nest panels across the full width, which usually gives better utilisation on larger sizes and on styles with side seams. The trade-off is an extra slitting operation and, on some qualities, a visible crease line down the fold.
For a standard tubular body tee, check the tube diameter against your largest size before accepting the mill's quality. Discovering at cutting stage that XXL does not fit the tube is an expensive correction.
How consumption feeds the FOB price
Fabric consumption is the first line of a garment costing, and everything downstream depends on it being right.
Take the worked example: 2.71 kg per dozen at a fabric price of USD 5.50 per kg gives a fabric cost of USD 14.91 per dozen, or USD 1.24 per piece. On a tee selling FOB at USD 2.10, fabric is 59 percent of the price.
Which is why a consumption error is expensive in a way other costing errors are not. Overstate by five percent and your quotation is USD 0.06 higher than it needs to be, enough to lose an order in a competitive bid. Understate by five percent and you absorb that loss across every piece, and on a 100,000-piece programme that is USD 6,000 gone.
Formula against CAD marker
A CAD marker gives the real figure, because it places actual pattern pieces on actual fabric width and reports utilisation. So why use a formula at all?
Timing. A buyer asks for a price on Tuesday and wants it Wednesday. Patterns are not ready, the fabric width is not confirmed, and the CAD room is working on live orders. The formula gives a defensible number in two minutes.
In practice the formula runs within three to five percent of the marker for basic styles. It tends to run slightly high on small sizes, where the fixed allowance is proportionally large, and slightly low on styles with a lot of panel shaping.
The working method most costing teams settle on: quote from the formula, confirm from the marker, and book fabric only after the marker is made. If the marker comes back more than five percent away from your formula figure, check the allowance you used before you check the marker.
Where the formula stops working
This calculation treats the garment as two rectangles. It works for a basic tee because the curved areas it over-counts roughly cancel against the neck rib, sleeve hem and shoulder seam it ignores. In practice it lands within a few percent of a physical marker.
It becomes unreliable for:
- Raglan sleeves — panel shapes differ enough that the rectangle assumption fails
- All-over prints and engineered stripes — matching the repeat adds 5 to 15 percent
- Heavy rib or waffle structures — GSM varies across the panel
- Very small sizes — a fixed allowance becomes proportionally too large
- Tubular fabric — body width is constrained by the tube diameter, so if half chest plus allowance exceeds half the tube width you either change diameter or accept the waste
For anything beyond a basic style, use this figure for costing and confirm against a CAD marker before booking fabric.
Consumption is not the same as booking quantity
The number this calculator gives you is what the garments consume. What you book from the mill should be higher, because roll ends, shade lot changes and short rolls all cost fabric that never reaches the cutting table. Adding 2 to 3 percent on top of the wastage figure at booking stage is normal practice.
Three mistakes that show up repeatedly
Using full chest instead of half chest. This doubles the consumption. Most measurement charts give half chest, but not all of them, so check before you calculate.
Mixing units. Everything must be in centimetres. If the buyer's specification is in inches, convert first.
Taking body length from the wrong point. HPS and centre back give figures that differ by 2 to 3 cm, which is enough to matter across a large order.
Frequently asked questions
How much fabric does one t-shirt need?
A standard adult t-shirt in 180 GSM single jersey uses about 0.20 to 0.23 kg, or 2.4 to 2.8 kg per dozen including wastage. Heavier fabric or a longer body raises this proportionally.
Why is fabric consumption calculated per dozen?
Garment costing in Bangladesh and most export markets is quoted per dozen, so fabric booking follows the same unit. Per-piece figures carry too many decimal places to work with comfortably.
Does GSM change consumption or only weight?
Only weight. The area of fabric a garment needs is fixed by its measurements. GSM converts that area into kilograms, so a 200 GSM version of the same tee uses the same number of square metres but weighs about 11 percent more.
What wastage percentage should I use?
Between 10 and 15 percent for knit t-shirts. Use the lower end for simple styles in a well-run cutting room, and the higher end for printed goods, small sizes, or a fabric you have not run before.
