Production calculator
Calculate sewing thread per garment and cones per order from seam lengths and measured thread-to-seam ratios for each stitch type, with a wastage allowance.
Method note: Thread suppliers publish their own consumption guides. Use measured ratios for your product whenever possible.
Thread per garment
93.7m
Thread per piece (m) = Σ(seam length × ratio) / 100 × (1 + wastage / 100)
| Symbol | Meaning | Unit |
|---|---|---|
| S_i | Seam length for stitch type i | cm |
| r_i | Thread consumed per cm of seam for that stitch | cm/cm |
| w | Wastage allowance | % |
Ratio = thread length unpicked / seam length it came from
For each seam, thread = seam length × ratio. The calculator adds all seams, converts to meters, adds the wastage percentage, and multiplies by the order quantity. Cones = total thread / meters per cone, rounded up.
See thread consumption for the ratio method.
The default rows are a T-shirt: overlock seams 250 cm at ratio 18, coverstitch 240 cm at ratio 16, and a label at ratio 2.5, with 12% wastage, 4,000 m cones and 5,000 pieces.
Split the cones by thread type and color according to the order's color breakdown. Remember that each machine needs a full set of cones in each color, which can raise the number of cones for short runs.
Measure them: sew 10 cm of seam on the production fabric at the production SPI, unpick all threads, measure their straightened length and divide by 10. The default ratios are examples only.
Enter separate rows for needle threads and looper threads if you buy them as different thread types, each with its own measured ratio.
How to calculate sewing thread consumption per garment using seam lengths and measured thread-to-seam ratios for each stitch type, then convert it into cones per order by color and ticket.
The stitch classes used in garment making, how each is formed, where it is used and its strengths and weaknesses. Based on the ISO 4915 stitch classification, with the common stitch numbers you will see on spec sheets.
How to choose sewing thread for garments: core-spun, spun polyester, filament and textured threads, ticket numbers and sizes, matching thread to fabric, seam and needle, and the thread-related causes of seam failures.
A garment bill of materials lists every material needed to make a style, with specification, placement, consumption and supplier. How to structure a BOM, calculate quantities by color and size, and avoid the errors that cause shortages.