Take 10cm of elastic. Stretch it until it feels comfortably tight, then measure that length.
Measure where the elastic will sit.
Lower % = Tighter fit. (Standard Ribbing is ~80-85%)
Extra length added to overlap and sew the ends.
Why Use This Tool?
Includes a "Stretch Tester" to analyse your specific elastic.
Calculates exact cut lengths for Waistbands, Cuffs, and Neckbands.
Works for both Elastic and Knit Ribbing.
Prevents garments from slipping down (too loose) or digging in (too tight).
How to Use It
Step 1
Test your elastic: Hold a 10cm section against a ruler. Stretch it to a "comfortable" tension.
Step 2
Enter the stretched measurement into the "Stretch Tester" to find your Stretch %.
Step 3
Enter your body measurement (Waist, Wrist, etc.).
Step 4
Select your seam allowance.
Step 5
Click "Calculate" to get the exact length to cut.
Frequently Asked Questions
What is "Comfortable Stretch"?
Do not stretch the elastic to its absolute snapping point! Stretch it until it feels firm but still has a little "give" left. This ensures the waistband will hold you up without digging in.
Does this work for Neckbands?
Yes. For t-shirt neckbands (ribbing), the standard factor is usually 80-85% (or 0.8). You can use the manual "Stretch Factor" slider to set this directly if you know it.
Why is the "Cut Length" different from the "Finished Length"?
The Cut Length includes the overlap or seam allowance needed to join the ends of the elastic together.
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