Zipper Length Calculator

Find the correct zipper length for your seam opening, including the right buffer for invisible, regular, and separating zippers.

Seam opening length

Zipper type

Invisible

+1″ buffer — zipper stop sits above seam

Regular / lapped

+½″ buffer — standard lapped or centered

Separating

Exact match — full-length jacket/coat zip

Add buffer (+1″)

Standard zipper sizes

7″9″10″12″14″16″18″20″22″24″

Zipper lengths vary by manufacturer. Always verify the sewn length (tape, not pull) when purchasing. Invisible zippers can be shortened from the bottom; regular zippers from the top.