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.

Quick answer: Measure the window seat itself, not the old cushion: wall to wall at the back and along the front edge, and the depth from the wall to the front edge. If the walls aren't square, use the shorter length. For bay windows with angled ends, take the back length, front length and depth, or trace a paper template, and choose a tapered cushion.

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 centre 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 colour runs through the fibre. 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.

Frequently asked questions

Should a bay window seat use one cushion or several?

Three cushions usually work best: a long center piece and two angled end pieces. They are easier to lift, clean and fit than one large cushion. Measure each section separately or make one template for each. See window seat cushions.

What fabric works for a sunny window seat?

Sunlight through glass fades many fabrics. Sunbrella resists fading and repels most spills, which suits a busy family nook. Velvet looks rich but fades faster in strong direct sun. Order fabric swatches to see colours in your own light. Swatch costs come back as a credit.

How tight should a window seat cushion fit between walls?

Give us the exact wall-to-wall measurement and we cut to it, within ±0.5″. It is better to be slightly snug than loose, because gaps at the ends are noticeable. If the walls aren't square, measure at the back and the front.

Do window seat cushions need ties?

Usually not between walls, because the walls hold the cushion in place. For open-ended seats, ties or Velcro on request help stop sliding. A zippered cover makes it easy to remove the fabric for washing or replacement later. Measure the seat, not the old cushion.