Commonly Used Formulas with Examples

For custom drapery, here are commonly used formulas with examples for calculating fullness and yardage.

Formulas

Fullness = (#Cut x Fabric Width) / Overall Width

Number of Cuts = Overall Width x Fullness = _____  / Fabric Width = Number of Cuts (round up to whole number)

Cut Length Including Repeat

• Finished Length + Cutting Allowance = Cut Length of Solid Fabric
• Cut Length of Solid Fabric / Length of Repeat = A (round up to whole number)
• A x Length of Repeat = Cut Length Including Repeat
  • Equivalent Number 48” Cuts: (Number of Cuts x Fabric Width) / 48” = Number of Cuts Invoiced (round up to even number)

Yardage = [Number of Cuts x Cut Length (allow for repeat)] / 36

Ruffling

• (Size of Ruffle +1 x 2) = Cut Length of Ruffle
• (Coverage Area for Ruffle x 3) / Width of Fabric = # Cuts for Ruffle (round up to whole number)
• # Cuts for Ruffle x Cut Length of Ruffle) / 36 = Yardage
  • Swag Width (Standard) = [Board Width / (# Swags + 1)] x 2

Circumference = Diameter x pi (3.146)

To find the circumference of table cloth for fringe yardage:

• Take (diameter x 3.146) divided by 36 (round up) (this gives you the amount of yardage needed for fringe)

Examples

Examples for 1 Pair Drapes (125” Wide x 90” Long (24” Repeat, 48” Wide Fabric), Lined, 250% Full, 6” Returns Right & Left)

Cut Length (solid fabric)

90" (finished length) + 16" (allowance for hem & header) = 106" (cut length)

Cut Length (if fabric has repeat)

106 / 24 = 4.41 (cut length / repeat)

4.41 = 5 (round up your answer)

5 x 24 = 120" (round up answer x repeat = new cut length)

Overall Width

125" (rod width) + 4" (constant 4" overlap) + 12" (left return & right return (6 + 6 = 12)) = 141" (overall width)

250% Full is 2.5 x Overall Width: 2.5 x 141 = 352 1/2 = Tabled Width

Fullness

352 1/2 / 48" = 7.34 (tabled width / width of fabric = number of widths needed)

8 x 120" = 960" (number rounded up or down for exact number of widths needed x cut length - A)

960" / 36" = 26.67 yards (A / 36" per yard = 27 yards needed)