Stitching Thread Length Calculator

Worked Example

Estimation method: Conservative geometry model; Seam length: 30 cm; Number of identical seams: 1 seams; Hole pitch: 3.85 mm; Total stack thickness: 3 mm; Sample seam length: 10 cm; Sample thread consumed (excluding tails): 40 cm; Working tail per end: 12 cm; Additional allowance: 15 %.

Method: Conservative saddle-stitch model; Stitch holes per seam: 78; Thread before allowance: 177.66 cm; Total thread to cut: 204.31 cm (2.04 m).

How It Works

• Geometry: H = floor(length mm / pitch) + 1; travel cm = H × (pitch + 2 × stack mm) × 2 / 10.
• Measured mode: travel cm = target seam cm × sample consumed thread cm / sample seam cm. Measure consumed thread separately from unused tails.
• Add two working tails per seam, multiply by seam count, then add the chosen percentage allowance.

seam:  o---o---o---o---o---o   <- pitch between holes
pass 1: \   /   \   /   \      <- needle A
pass 2:  /   \   /   \   /     <- needle B

How to Use

1. 1Use the model until you have a comparable sample seam.
2. 2Measure sample thread consumed excluding unused tails, and record thread, pitch, stack and tension.
3. 3Choose tail length and extra allowance explicitly; avoid adding the same tail twice.
4. 4For machine stitching, use machine-specific top/bobbin measurements rather than this saddle-stitch model.

FAQ

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