18" Square Polyester Fiber Pillow Insert
The 18" square is the most popular throw pillow size in home décor — and having the right insert on hand means every quilted pillow cover project can be completed immediately. This polyester fiber pillow insert delivers a full, lofty appearance with comfortable support. For quilters making 18" pillow cover blocks, sampler blocks converted to pillows, and standard decorative throw pillow projects. The 12"x16" lumbar insert covers the rectangular format, with Perfect Loft loose fill for everything custom.
Size: 18" x 18" | Fill: Polyester fiber
Frequently Asked Questions
Why is 18" the quilter's pillow size?
It matches the finished size of many classic quilt blocks — a 16–17" cover over an 18" insert turns a single sampler block into a plump finished pillow.
What cover dimensions give the fullest look?
Finish the cover at 16–17" square — slightly undersizing the cover is the trick to crisp corners and no saggy fabric.
Envelope back or zipper for quilted covers?
Envelope backs are the fast washable classic; zippers give a tailored finish. Either works over this insert — the insert pops out for separate washing both ways.