How to use this calculator
- Enter or choose outline points (x, y).
- Enter or choose measurements in.
- Enter or choose pieces per garment.
- Enter or choose garments.
- Enter or choose cuttable fabric width.
- The piece area updates as you type. Use Copy result or Share to keep it.
Method
Area = ½ |Σ (xᵢ·yᵢ₊₁ − xᵢ₊₁·yᵢ)|; Total = Area × Pieces × Garments; Length = Total ÷ (Width × Marker efficiency)
- xᵢ, yᵢ
- outline corners in order (1 in = 2.54 cm)
- Marker efficiency
- pattern area ÷ marker area
Worked example
- The outline is a trapezoid: (50 + 40) ÷ 2 × 70 = 3,150 cm².
- Two pieces per garment × 1,000 garments = 6,300,000 cm² = 630 m².
- Length = 630 ÷ (1.5 m × 0.80) = 525 m.
Each piece is 3,150 cm², and 1,000 pairs need about 525 m of 150 cm fabric at 80% marker efficiency.
What the result means
Use the total area to estimate fabric before a marker is made, and to compare a marker’s efficiency once it exists.
Assumptions and limits
- Points are in order around the outline and the outline does not cross itself.
- Curves are approximated by straight lines between points; add more points along curves for a closer area.
- Seam allowances must be included in the outline you trace.
Questions
Does the starting corner matter?
No. Any start point, clockwise or anticlockwise, gives the same area.
What marker efficiency should I use?
Your CAD system’s figure for similar styles; it depends on the pieces, sizes and fabric width.