Cushions for window seats and built-in benches
Built-in seating is almost never a standard size. Here is how to measure an odd space, choose between one cushion and several, and pick a thickness that suits how you will use the seat.
Why built-ins are tricky
Store-bought cushions come in standard sizes. Window seats, built-in benches and kitchen banquettes almost never do. They are built to fit a room, walls are rarely perfectly square, and an inch too wide means a cushion that bows up in the middle. An inch too narrow leaves a gap you will notice every day. That is exactly why built-ins are the best case for a made-to-measure cushion.
Measuring an odd space
- Width in three places. Measure along the back wall, through the middle and across the front edge. Use the smallest number so the cushion slides in.
- Depth at both ends. Measure front to back at the left and the right. Again, use the smaller one.
- Check for anything in the way. Window trim, a radiator cover or the lip of a storage lid can steal space. Measure the flat area the cushion will actually sit on.
- Trace anything that is not a rectangle. For angled bays or curved ends, lay craft paper on the seat, trace the edge, then measure the paper flat on the floor. Keep the template, because it is the most reliable record of the shape.
The full step-by-step, with diagrams and a printable sheet, is in our measuring guide.
One cushion or several
- One long cushion looks clean and uninterrupted. It works well for shorter seats.
- Sections make sense for long seats (past about six feet), L-shaped banquettes, and benches with storage underneath. Each piece is easier to lift, flip and clean, and one worn section can be replaced on its own.
How thick
Thickness is about how you use the seat.
- Dining banquettes and entry benches: a thinner cushion keeps the seat at a comfortable table height and feels firm.
- Reading nooks and window seats: a thicker cushion is softer for curling up for an hour.
- Check the height. Sit on the bare seat and imagine adding the cushion. At a table, your knees still need to fit underneath.
Details that matter
- Back cushions. For banquettes, back cushions make a seat you can linger in. Measure them separately: width, and height from the top of the seat cushion.
- Fabric for the room. Kitchen banquettes see spills, and sunny windows fade color. A durable, easy-clean performance fabric is worth considering for both. See indoor vs outdoor fabric.
- Zippered covers come off for cleaning, which matters more indoors than people expect.
- Edge style. A boxed cushion with piping looks tailored and built in. A knife-edge cushion looks softer and more casual. Both are explained in cushion styles.
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Questions
My window seat is not square. Can it still have a custom cushion?
Yes. Measure the width in three places and the depth at both ends, and use the smallest numbers. For angled or curved shapes, trace a paper template.
Should a window seat cushion be one piece or several?
One piece looks cleanest on shorter seats. For long seats, L-shaped banquettes or benches with storage lids, sections are easier to handle and clean.
How thick should a window seat cushion be?
It depends on use. Thinner is better for dining and perching, thicker is better for lounging. Check that the added height still works with any table or window ledge.
What fabric is best for a kitchen banquette?
Something durable and easy to clean, like a performance fabric, with a zippered cover so it can come off for cleaning.