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A Reading by NateTrapezoid & Angled Cushions

A sage angled window seat cushion, and the five mistakes it doesn't make

No gap at the angle, no white to stain, no pillow pile. A child's window seat gets the geometry right and lets the books do the styling.

The quick answer

An angled window seat cushion should be cut to the bay's real angle, not stopped square, so no wedge-shaped gap opens against the side window. Measure the back edge, the front edge and the depth at each end, and trace the angle on paper. For a child's seat, a mid-tone woven fabric with self piping forgives marks.

Read by

The Pattern Engineer of DetroitPublished Updated 4 min read

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Five pins, five decisions

Five pins, from the angled right end to the slippers parked under the seat.

Pinned: Sage green linen-look angled window seat cushion with self piping in a child's bay window, open picture book and slippers
  1. Open picture book

    A book left open shows the seat's real job as a reading spot at child height.

  2. Angled end

    The right end is cut to the bay angle so there is no wedge-shaped gap against the side window.

  3. Self piping

    Sage-on-sage welt gives a tailored edge without a pale line for little hands to mark.

  4. Child's slippers

    Slippers under the seat show the height is right for a small child to climb up.

  5. Low bookcase

    Books within reach of the seat make the nook usable without an adult.

  1. Open picture bookA book left open shows the seat's real job as a reading spot at child height.
  2. Angled endThe right end is cut to the bay angle so there is no wedge-shaped gap against the side window.
  3. Self pipingSage-on-sage welt gives a tailored edge without a pale line for little hands to mark.
  4. Child's slippersSlippers under the seat show the height is right for a small child to climb up.
  5. Low bookcaseBooks within reach of the seat make the nook usable without an adult.

Five mistakes this window seat avoids

  • Stopping square at the bay. The right end follows the bay angle, so there is no wedge of gap for a book, or a small foot, to fall into.
  • White in a child's room. Sage is a mid-tone and forgives fingerprints that white would frame.
  • A pale contrast welt. Sage-on-sage self piping gives a tailored edge with no light line to get grubby.
  • Pillows on the seat. Only an open book sits there, so the whole length stays usable.
  • Books out of reach. A low bookcase beside the seat means a child picks a book without an adult.

Reading the corner by the numbers

A photo can't give me inches, partner, but it gives me decisions, and each one here holds up.

The seat sits under three sash windows. Daylight comes in from three sides, soft and even, so no hard shadow hides a sloppy edge. That is the job of a trapezoid cushion: meet the side wall along its real line.

The fabric is a sage linen-look weave. The props do measuring work: felt slippers under the seat say the height suits a small climber, and brass latches and pine boards warm a white room.

To copy it, trace the angle. Angles are just lengths in disguise: tape paper into the corner, mark the wall line, then measure back edge, front edge and depth at each end, plus any ledge. The trapezoid cushion calculator and the paper template guide walk it through. What angle does your bay turn?

A real project

When 35 in didn't add up

A dog owner in the US wrote to the workshop about a long angled window seat, in a linen the workshop called easy to clean and washable at 86°F (30°C). The first sketch was blurry, so it came again.

Drawn to scale, the slanted edges did not come out at the written 35 in (89 cm). The corners were not square.

So the cut followed the main dimensions: a 112 in (284 cm) long edge, 18 in (46 cm) deep, ends of 32.5 in (83 cm) and 31 in (79 cm), a short edge near 48.5 in (123 cm). The diagonals followed the geometry. The buyer confirmed, and production began.

When a window seat's corners aren't square, cut the trapezoid cushion from the edges against the walls and let the diagonals follow.

Nate
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Cut sheet for the sage seat

ShapeTrapezoid, right end cut to the bay angle
FabricSage linen-look weave, mid-tone
PipingSelf piping, sage on sage
EdgeBox edge
MeasureBack edge, front edge, depth at each end, any ledge
Out of squareCut from the edges on the walls; diagonals follow
UndersideOptional non-slip fabric backing, whole base

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Have it made

Have this made — ask Nate’s workshop

Every edge and both diagonals, to the nearest 1/4 in. If the numbers do not close, the workshop will say so on the call. — Nate

Leave your details and the workshop will call you to confirm measurements, fabric, foam and piping. No prices, dates or payment on this page: it is a request, not an order.

Fabric · Foam · Pipingwhat the workshop will confirm with you

Fabric
Sage linen-look weave, mid-tone
Foam
The core: its density and thickness set the feel.
Piping
Self piping, sage on sage
Only for this request: no marketing calls or texts. Outside the US, add the country code.
In inches: length × depth × thickness, plus any angles or cut corners.

* Required. A member of the workshop team will call you to talk it through; nothing is charged and nothing is made until you have agreed on every detail with them.

We use these details only to answer this request and make your cushion: your name and contact details, the cushion details and photos you send, the page you came from and the ad or link that brought you, if any. The workshop that makes the cushions receives them. We don't sell them or share them for advertising, and we delete requests after 24 months. Privacy notice for requests.

Nothing is made or charged until you approve the details.

Want to pick the shape and add photos? Use the full quote form

Questions from angled-seat buyers

  1. A common question

    Can the piping be a different color from the cushion, and which colors can I pick?

    The workshop's answer

    Yes. Contrast piping comes from the same range as the fabrics. Pairs made include one linen-look shade piped in another, green corduroy with cream corduroy piping, a stripe with brown piping, and linen piped in velvet.

  2. A common question

    Will a non-slip base harm the wood of my bench, and does it cover the whole bottom?

    The workshop's answer

    It won't harm wood. The non-slip base is a fabric backing, not an adhesive or rubber coating. It covers the entire underside, since it can't be done as a partial strip, and it isn't visible once the cushion is in place.

  3. A common question

    My window seat is wider than 28 inches and has a small ledge. Can you still make it?

    The workshop's answer

    Yes. Every size and thickness can be customized. Send the exact measurements, including the depth of the ledge.

Questions buyers ask next

How do I measure an angled window seat for a trapezoid cushion?

Measure the back edge against the wall, the front edge, and the depth at each end, then trace the angle on paper. If the drawn slant doesn't match your tape, the corners are out of square and the cut follows the wall edges.

What color hides marks best on a kids' window seat?

A mid-tone woven fabric. Sage is calm in a bedroom and hides marks better than white, and self piping avoids a pale edge line that small hands would find first.

Can a linen window seat cover be washed?

The linen in the angled-seat story here was described as easy to clean and washable at 86°F (30°C). Check the care note for your own fabric first, since care differs from one weave to another.

± 1/4 in — Nate