HOME DECOR TOOL
Pillow & Cushion Cover Calculator
Calculate exact fabric cuts for envelope-back and zippered cushion covers with built-in negative ease for plump, professional corners.
Calculate Cuts
Front Panel Cut Size:
18.0 × 18.0 in
Back Overlap Panels (Cut 2):
18.0 × 13.0 in
Cushion Field Manual
The 1-Inch Negative Ease Secret
- Why Cut Exactly to Insert Size? When you add 1/2" seam allowances around the cut panel, the finished cover sews up 1" smaller than your insert. This tension fills out the corners and eliminates droopy fabric wrinkles.
- Envelope Back Overlap: The two back flaps overlap by 4 inches to prevent the pillow insert from peeking out during use.
The Math Formula
• Front Cut = Insert Dimension (sews 1" smaller)
• Envelope Back Pieces = Width × ((Height ÷ 2) + 4" overlap)
• Envelope Back Pieces = Width × ((Height ÷ 2) + 4" overlap)