How to Accurately Measure a Pillow Cover
Pillow cover sizes are based on the measurement from seam to seam. A pillow cover may sometimes appear smaller if you are measuring it from the front because the sides may be folded in a bit. For this reason, to get the most accurate measurement, remove the insert, turn the cover inside out, lay it flat, and measure it from seam to seam. The photos below show a pillow cover that measures 19 inches. Notice how the yardstick is lined up with the seam.
1. Turn pillow cover inside out and lay it on a flat even surface.
2. Line up measuring stick or tape with the seam on one side
3. Line up the measuring stick/tape with the seam on the opposite side. In the photo below, the pillow cover measures 19 inches wide.