How much should I reduce elastic from body measurement?

Waistband elastic is typically 80-90% of waist measurement. Cuffs need 75-85%. Necklines need 85-95%. The exact reduction depends on elastic type and stretch — firmer elastic needs less reduction.

How much overlap do I need for joining elastic?

Allow 2-2.5cm overlap for joining elastic ends. Overlap the ends and zigzag or use a box stitch. For enclosed casings, add the overlap to the cut length.

What width elastic should I use?

Waistbands: 2-4cm wide. Cuffs: 1-2cm. Necklines: 0.5-1cm. The casing must accommodate the elastic width plus ease for it to slide through (add about 1.5cm to the elastic width).

What type of elastic should I use?

Braided elastic narrows when stretched — good for casings. Knitted elastic retains width — good for direct sewing. Woven elastic is firm — good for waistbands. Clear elastic is for swim and activewear.

SewCalcs

Elastic Calculator — Elastic Length

Calculate elastic length for waistbands, cuffs and casings.

Body Measurement

Circumference where elastic sits

Application

Elastic Width

Overlap for Joining

How We Calculate This

Elastic length is a percentage of the body measurement, reduced to create comfortable tension. The casing width accommodates the elastic plus ease.

The formula

Elastic length = Body measurement × Reduction ratio + Overlap

Casing width = Elastic width + 1.5cm ease

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.