Elastic width plus 1/4 inch seam allowance is used in the casing calculation. What is this formula called?

Elastic width plus 1/4 inch seam allowance is used in the casing calculation. What is this formula called?

• A. Elastic width formula
• B. Seam allowance formula
• C. Casing formula
• D. Hem allowance formula

Answer: (C)

Sizing the fabric strip for the elastic casing uses the elastic width plus a small seam allowance, typically 1/4 inch, to determine the correct casing size. This specific calculation is called the casing formula. It’s different from a general seam allowance formula (which applies to any seam, not just a casing), an elastic width formula (which would focus on the elastic itself), or a hem allowance formula (which relates to finishing the bottom edge). The casing formula directly governs how long or wide the fabric tunnel should be so the elastic fits properly and you can sew the casing closed.

Sizing the fabric strip for the elastic casing uses the elastic width plus a small seam allowance, typically 1/4 inch, to determine the correct casing size. This specific calculation is called the casing formula. It’s different from a general seam allowance formula (which applies to any seam, not just a casing), an elastic width formula (which would focus on the elastic itself), or a hem allowance formula (which relates to finishing the bottom edge). The casing formula directly governs how long or wide the fabric tunnel should be so the elastic fits properly and you can sew the casing closed.