The five measurements a T-cushion order needs — width between arms, seat depth, arm wrap per side, front overhang and thickness — plus the four mistakes specific to ear cushions and what to do when the ears do not match.

How to measure an oval cushion — long axis tip to tip, short axis across the middle, thickness at the seam — plus the quarter-inch rule that tells a true oval from a circle before you order.

How to measure a trapezoid cushion — read width at three stations, record both widths, take depth along the slanted edge. With verified Hampton Bay trapezoid dimensions and the rectangle-that-almost-fits trap.

A factory method for measuring rounded cushion corners — the cardboard trick, the four numbers our cutting form needs, common patio radii, and the dog-ear problem that happens when you skip the radius.

Curved outdoor cushion guide: why patio frames curve, chord-and-camber measuring for bowed seats, curved-front benches, round and racetrack sets, weather specs for shaped pads, and template ordering.

D-shaped cushion guide: the semicircle-with-flat-back geometry of window seats and corner chairs, measuring diameter and chord, radius versus template methods, and where D-shapes beat rectangles.

Papasan cushion measuring from first principles: the bowl rim diameter and base diameter that define the round, thickness for sink-versus-support, and how to order a replacement that actually fits the frame you own.

Measuring round cushions the factory way — why the tape must cross the center, what an ovaling old cushion costs you, frame diameter vs cushion diameter, and the two numbers every round order needs.