How to Measure a Window Seat Cushion (Including Bay Windows)

A window seat is almost always built in, which is why a store-bought cushion rarely fits. The good news is that measuring one takes about five minutes and a tape measure. Here's how to do it for a straight seat, a bay window and a corner nook.

What you need

• A metal tape measure
• A pencil and paper
• For bay windows: a large sheet of paper or cardboard to make a template

Measure the seat, not the old cushion

Old cushions shrink, sag and lose their shape. Measure the wooden seat itself, from wall to wall or end to end. If the seat has a lip or trim along the front, measure to the inside of it.

Straight window seats

1. Length: measure from one end of the seat to the other along the back wall, then again along the front edge. If the two numbers differ, the walls aren't square, so use the shorter one.
2. Depth: measure from the back wall to the front edge at both ends and in the middle. Use the smallest number.
3. Thickness: decide how high you want to sit. Most window seats take a 2 to 4 inch cushion. Check that the cushion won't block a window latch or sill.

Bay windows with angled ends

A bay seat is usually wider at the back (along the glass) than at the front, or the other way round. You need three numbers:

1. Back length along the wall or window.
2. Front length along the front edge of the seat.
3. Depth from back to front, measured straight, not along the angle.

If the angles are unusual, lay paper over the seat, trace the outline, and take your measurements from the tracing. For angled ends, choose a tapered cushion.

Corner and wraparound seats

For a seat that turns a corner, measure each leg of the L along the back wall and along the front edge, plus the depth of each leg. Then choose a one-piece L-shaped cushion, or a T-shaped cushion for a seat with a center section.

Choosing fabric

A window seat gets more sun than most furniture. For a seat in strong sun, Sunbrella is the safe choice because the color runs through the fiber. For a reading nook with less direct light, Warwick fabrics, velvet and faux leather feel softer and warmer.

Finishing touches

Add bolsters at each end to lean against, and a few throw pillows against the glass. A zippered cover makes it easy to clean or replace the fabric later.

Ready to order?

Enter your measurements in the window seat cushion builder and the price updates as you go, or browse all window seat cushions.