Custom Outdoor Cushions: How to Measure and Standard Sizes

Replacement cushions that slide around, gap at the arms or hang over the front rail almost always come from one mistake: measuring the cushion instead of the frame. For custom outdoor cushions and for standard sizes off the shelf alike, the numbers that matter are the seat opening, the back height and the thickness the frame can hold. Measure those correctly and you can buy with confidence.

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Quick answer: measure the seat width at the front and back, the depth from front rail to back frame, and the back height from the seat deck to the top of the back. Note the shape, any curves or notches, and where the ties go. Then compare those figures with standard sizes, which range from 18 by 18 inches for dining chairs up to 28 by 28 inches and larger for deep seating.

From there, choose thickness, edge style and fill to match how the furniture is used and how much rain it sees.

How to Measure for Custom Outdoor Cushions

Gather a tape measure, a notepad and, for curved or odd shapes, a sheet of kraft paper to trace a template. Remove the old cushions first. Old cushions compress and shrink over time, so their sizes can mislead you.

1. Seat width: measure side to side at the front of the seat, then again at the back. Many chairs taper, and a tapered (trapezoid) cushion fits better than a square one.
2. Seat depth: measure from the front edge of the seat frame to the back frame or back cushion stop.
3. Back height: measure from the seat deck to the top of the back frame, or to where you want the cushion to end.
4. Back width: measure at the top and bottom if the back is angled or curved.
5. Thickness: measure how much room there is between the seat deck and the top of the arm. Most seat cushions fit well when they sit 1 to 2 inches below the arm top.
6. Ties and notches: note where the ties attach and any notches needed around posts or arms.

For curved seats, lay kraft paper on the frame, trace the outline and mark the tie points. Many shops that make custom patio cushions accept paper templates or photos with measurements.

Standard Outdoor Cushion Size Chart

Off-the-shelf cushions follow common sizes. If your frame falls within about half an inch of one of these, a standard cushion usually fits well.

Deep seating replacement cushions for outdoor furniture are the most size-sensitive. A 25×25 cushion in a 26×26 frame leaves a visible gap, while a 27×27 cushion in the same frame bulges and pushes the back cushion forward. Measure carefully and round down rather than up if you fall between sizes.

Seat Cushions, Back Cushions and One-Piece Styles

Seat and back sets

Deep seating furniture usually uses separate seat and back cushions. The back cushion typically matches the seat width and stands 18 to 24 inches tall. Deep seat outdoor cushions work best when the seat and back are the same thickness family, so the set looks balanced.

High back outdoor chair cushions

Stacking and adjustable chairs often use a single long cushion with a hinge seam where the seat meets the back. Measure the seat depth and back height separately, then note the hinge location so the fold sits right at the joint of the chair.

Chaise lounge replacement cushions

Chaise cushions have multiple hinge points. Measure the total length and the length of each section (foot, seat and back) so the seams line up with the chaise’s pivot points.

Swing cushions

Replacement 3 seat swing cushions usually come as one long seat with a separate or attached back. Measure the swing seat platform inside the arms and the back from the seat to the top rail. Outdoor swing cushions for 3 seaters often measure around 60 to 72 inches wide, but frames vary, so measure your own.

Round outdoor cushions

For round seats, measure the diameter at the widest point. Common sizes run 15 to 20 inches for bistro chairs.

Box Edge vs Knife Edge vs Tufted

Edge style affects both look and fit.

• Box edge: a side panel (boxing) joins the top and bottom, giving square sides and a tailored look. Standard on deep seating. Holds its thickness evenly.
• Knife edge: the top and bottom sew directly together, so the cushion is thicker in the middle and thin at the edges. Lighter and less formal, common on dining chairs and pillows.
• Tufted or button: stitching through the cushion keeps fill in place. Common on chaise and bench cushions.
• Welting or piping: a corded trim along the seams adds structure and a finished edge.

Thickness, Fill and Fabric

Thickness should match the frame and the use. Dining chairs rarely need more than 2 to 3 inches. Deep seating frames are built for 5 to 6 inches. Too thick a seat cushion raises you above the arms and makes a chair feel cramped.

Fill options

• Polyurethane foam with fiber wrap: comfortable and common. Holds water if soaked, so it suits covered areas.
• Quick-dry reticulated foam: open cells let water drain out. Best for uncovered decks and poolside seating.
• Polyester fiberfill: soft and affordable, but it flattens over time. Best for pillows and knife edge cushions.

Fabric

Solution-dyed acrylic is the most fade-resistant and mildew-resistant choice. Polyester costs less but fades faster in full sun. For busy families, look for fabric with a stain-resistant finish and zippered covers you can remove for cleaning.

Ties, Straps and Keeping Cushions in Place

Ties usually sit at the back corners of the seat cushion and at the top or bottom of back cushions. Note the frame spot each tie wraps around. Hook-and-loop straps, non-slip backing and zippered covers with grip bottoms are alternatives. On benches and swings, ties at both ends keep long cushions from sliding forward.

Troubleshooting Fit Problems

• Gap at the back or sides: the cushion is undersized. Add a back pillow or reorder closer to the frame size.
• Cushion bulges or buckles: it is oversized. Size down half an inch to an inch.
• Cushion slides forward: add ties or non-slip backing, or check that the back cushion is thick enough to hold it.
• Seat feels too high: choose a thinner cushion so you sit 1 to 2 inches below the arms.
• Cushions stay wet: switch to quick-dry foam and store cushions in a deck box during rainy spells.

General Cost Ranges

Standard-size outdoor cushions are the most budget friendly, from roughly $20 to $60 each for dining chairs and $60 to $200 per set for large outdoor cushions used in deep seating. Custom outdoor cushions cost more, often $100 to $300 or more per seat cushion depending on size, fabric and fill. Chaise and swing cushions sit at the higher end of each range because of their size. For odd shapes, curved frames or heirloom furniture, custom outdoor cushions are worth the extra cost; for square frames that match a standard size, off-the-shelf options save money.