Elastic Calculator

Woven elasticis the firmest option — it doesn’t narrow when stretched and holds its shape wash after wash. Best for waistbands and structural applications where you want a strong, reliable hold.

Knit elastic is softer and more comfortable against skin. It narrows slightly when stretched, so choose a wider width than you think you need. This is the best all-purpose elastic for most garments.

Clear elasticis a transparent polyurethane strip with very high stretch. It’s used to stabilise seams in stretch fabrics (necklines, shoulder seams) rather than to gather. Cut it shorter because it stretches much more.

Swimwear elasticis specifically designed to resist chlorine, salt water, and sunscreen. Regular elastic breaks down quickly in swimwear — always use the real thing.

Drawcord elasticis cut at the full opening measurement (plus overlap) because the wearer controls the tension by pulling the cord. It’s adjustable and forgiving.

Before cutting your final elastic, wrap it around the body part (waist, thigh, arm) at the intended tension. Overlap the ends and hold for 30 seconds. It should feel comfortable without digging in. If you can fit two fingers between the elastic and your skin, the tension is about right for “medium.”

Elastic stretch degrades over time. If your elastic doesn’t snap back to its original length after being pulled to 150% for a few seconds, it’s old stock or poor quality — don’t use it.

To replace worn-out elastic: carefully open the casing, pull out the old elastic, measure the opening, and use this calculator to cut a fresh piece. Pin the new elastic to a safety pin or bodkin, thread it through, overlap the ends, and stitch with a zigzag.

If the original elastic was sewn directly to the fabric (not in a casing), you’ll need to unpick the stitching. Consider upgrading to a casing method for easier future replacement.