Zipper Length Calculator — Correct Zip Size
Determine the correct zipper length for garments and projects.
Length of the zipper opening
Enter the garment type
How We Calculate This
The zipper length is the opening measurement plus 2.5cm for the stops and ease.
The formula
Minimum zipper = Opening length + 2.5cm
Round up to the next standard size available.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.