With a hanging chair, the old cushion is often so uniquely shaped that a "universal" replacement pad looks good in a photo but still slips around in the basket. Some seats are round, others oval, while others have a flat seat base with a separately padded back. That is why a new hanging chair cushion begins with the question of how the basket actually supports the cushion.

Hanging basket, wicker chair, or hanging swing: what is the seat shape?
Place a straight edge across the usable seat area and measure the maximum width and depth. For a round seat, the diameter helps; for an oval cushion, you need the long and short axes. Check where the cushion rests and whether it is allowed to extend over a raised edge. If you also want to pad the back, measure it separately. A single flat round cushion cannot replace a deeply molded, shell-like seat and back padding.
Custom replacement cushions instead of searching for the original
Especially with older hanging chairs, the original cushion is no longer available or the manufacturer only provides approximate external dimensions. Use the old cushion as a template if it still holds its shape. Otherwise, sketch the seating surface on the furniture. For an oval shape, the two main axes are only sufficient if the contour actually resembles an ellipse. For straight edges, cutouts, or an unusual multi-sided base, a dimensioned drawing is necessary. Strongly curved, three-dimensional molded cushions must be individually checked for feasibility.
A cushion that is also practical outdoors
For a hanging basket on the terrace, the cover is at least as important as the shape. UNIPOLSTR combines a foam core with a removable, waterproof, and UV-resistant cover that can be washed. Choose the thickness with the seat height in mind: in the basket, every additional centimeter of padding reduces the distance to the upper edge. If it will not be used for a long time, store the cushion in a dry place.
If only the existing fabric needs to be replaced, choose a round UNICOVR cushion cover or a custom-made oval cover. For a loose back cushion, there is the cushion cover. A deep, shell-shaped molded cushion should be checked for feasibility before ordering.
Which shape should I configure?
For a clear circular base, choose the custom-made round seat cushion, and for an elliptical seat area, the oval cushion. If your hanging basket has straight edges, cutouts, or a multi-sided floor plan, check the special-shape cushion. For a single loose back cushion, the custom cushion is an option. If you only need a new core to go under an existing cover, you will find the custom foam cut-to-size separately.