---
title: "Bay Window Cushion From Above: Where to Spend, Where to Save"
url: "https://cushionguide.com/readings/trapezoid-bay-window-cushion-top-down-view/"
section: "Readings"
author: "Nate Kowalski, The Pattern Engineer of Detroit"
author_url: "https://cushionguide.com/masters/nate/"
published: "2026-01-16"
updated: "2026-01-16"
keywords: "bay window cushion, trapezoid bench cushion, angled window seat cushion, bay window seat cushion, custom size cushion, made to measure cushion"
---

# A bay window cushion seen from above, and where the budget should go

*This is the photo I wish every buyer sent: straight down into a three-sided bay, every edge in view. From up here, partner, you can see where the money in a bay cushion goes, and where it only looks like it does.*

> **The quick answer:** On a bay window cushion, spend your care on the measurements and the foam, and save on decoration. Size and shape set most of a custom quote; thickness, the number of pieces, fabric type and tufting move it. Contrast piping is included at no extra charge, so a line of indigo is free, while a slant length that doesn't close is the expensive mistake.

![Top-down view of an oatmeal trapezoid window seat cushion fitted into a three-sided bay above pine floorboards](https://cushionguide.com/media/bay-window-cushions/trapezoid-bay-window-cushion-top-down-view-1600.webp "From above, the trapezoid template is clear: a long front edge, a shorter back and two angled ends following the bay.")

## Five pins on a bird's-eye bay

Five pins, read from the back window to the rug, each marked with what it costs or saves.

1. **Trapezoid template**: Long front edge, shorter back and two angled ends following the bay.
2. **Angled end**: Each end meets the side panel at the bay's own angle.
3. **Front edge piping**: The cushion stops level with the plinth so the piping lines up with the wood.
4. **Radiator**: Keep radiators in mind when measuring the plinth depth.
5. **Jute rug**: Warm natural textures balance the gray-white bay.

## Reading the bay from the ceiling

From overhead the template is plain geometry: a long front edge, a shorter back along the center window, and two angled ends meeting the side panels at the bay's own angle. Most bays turn at about 135 degrees. This one looks close, but a look is not a measurement.

The cushion stops level with the front of the white plinth, so the indigo piping lands on the same line as the painted wood below. A free design decision, doing a trim molding's work. Oatmeal [linen-look](https://cushionguide.com/fabrics/linen-look-fabrics/) reads warm against gray-white paint; pine boards and a jute rug carry that warmth down.

The cast iron radiator in the corner is the one thing to watch. Measure the plinth top itself, note the radiator on your drawing, and let the [bay window calculator](https://cushionguide.com/studio/bay-window-calculator/) check that your numbers close. Do yours?

## Spend here, save there

| Line item | Spend or save | Why |
|---|---|---|
| The drawing | Spend time | Front, back, depth and both slants, labeled |
| Foam density | Spend | About 2.0 lb/ft³ (32 kg/m³) keeps its shape for years |
| Contrast piping | Free | Included in any code at no extra charge |
| Tufting | Save | It raises the quote, and the cover can no longer come off |
| Pieces | Decide early | One piece or three changes the quote |

## Seven letters for a 104-inch bay

A buyer in the US had a bay seat 104 in (264 cm) across its widest side, too big for the order form, so they sent a drawing with every edge lettered: A and B at 4 in, C at 104 in, D at 57 in, E and F at 31 in, G at 24 1/2 in (62 cm), and asked how the piping color gets chosen. After one failed attachment and a resend, the workshop quoted it in the linen range, code L-24, with a custom order link.

Angles are just lengths in disguise, and those letters prove it. If C is the front and D the back, each end steps in 23 1/2 in and back 20 1/2 in behind a 4 in straight return: a slant of 31.2 in against the 31 they measured. Numbers that close within 1/4 in are numbers I can cut from.

## Three shape questions

**A common question:** Can you make a cushion for a bench that's rounded at one end, or for a half-round window seat?

**The workshop's answer:** Yes, from exact dimensions and a drawing. A 33 x 20 in (84 x 51 cm) bench cushion rounded at one end was quoted from the owner's shop drawings, and an arched seat about 67 x 47 in (170 x 120 cm) was drawn as a rectangle plus an arc.

**A common question:** My window is uneven and a piece of trim sticks out. Which width do I give you?

**The workshop's answer:** Send a rough sketch with every measurement and mark the trim or any wood that sticks out, since that throws numbers off. The workshop holds production until the shape is confirmed, and sometimes a small gap is the simplest fix.

**A common question:** Can I send you my own fabric, and how much would you need?

**The workshop's answer:** The workshop discourages it, because sending fabric in adds delays. Send a clear photo or the fabric's details instead, and it will look for an exact or very close match.

> On a bay window cushion, the free upgrade is contrast piping and the costly mistake is a slant that doesn't close. Check the drawing before the fabric.
>
> — Nate

> **Tailor's margin:** Add both diagonals to any bay drawing. If front, back, depth and slants close within 1/4 in, the shape is right; if they don't, measure again.

## On the cutting table: the bay seat

|   |   |
|---|---|
| Cushion | Trapezoid bay window cushion, one piece, box edge, angled ends |
| Fabric | Oatmeal linen-look (polyester) |
| Piping | Indigo contrast, top and bottom seams |
| Foam | About 2.0 lb/ft³ (32 kg/m³) high-resilience |
| Thickness | Drawn at the standard 4 in (10 cm) |
| Fit | Front edge level with the plinth face |
| Care | Zippered cover; machine wash, line dry |

## Questions buyers ask next

### Is a bay window cushion better in one piece or three?

One piece keeps a single clean front edge. Three pieces, one per panel, are easier to handle and suit seats whose lids lift. The number of pieces changes the quote, so decide first.

### Which bay measurement goes wrong most often?

The angled sides. A slant is always longer than the straight depth, and if front, back, depth and slants don't close as a shape, one of them is off. Take the depth at 90 degrees from the center.

### Does thickness change the price of a bay cushion?

It can. Size and shape set most of a custom quote, and thickness, the number of pieces, fabric type and tufting all move it. Ask for two thicknesses in one quote if unsure.

## Related at the atelier

- [Bay Window Cushion in Olive with Ivory Piping over a Radiator](https://cushionguide.com/readings/olive-trapezoid-bay-cushion-over-radiator-sitting-room/): Contrast piping is the right call on a bay window cushion when the fabric sits close in tone to the wall behind it.
- [Bay Window Cushion, Trapezoid Cut: Plain, Stripe and Texture](https://cushionguide.com/readings/oatmeal-trapezoid-bay-window-cushion-pink-piping/): On a trapezoid bay window cushion, keep the angled seat plain or softly textured and put stripes on rectangular pillows, because a stripe meets the angled ends on a slant.
- [Bay Window Cushion Makeover: Terracotta Trapezoid, Brown Piping](https://cushionguide.com/readings/terracotta-trapezoid-bay-window-cushion-brown-piping/): One terracotta trapezoid bay window cushion can make a white bay the warmest spot in a room, as long as everything around it stays pale and dark brown piping ties it to the brass and oak.
- [How do I measure a bay window seat for a cushion?](https://cushionguide.com/answers/how-to-measure-bay-window-seat-cushion/): Measure a bay window seat by sketching it from above and writing every edge length on the drawing: the back edge against the window, the front edge, each angled side, and the depth from front to back.
- [How do I label the sides on my trapezoid cushion drawing?](https://cushionguide.com/answers/trapezoid-cushion-drawing-label-sides/): Give every edge of the trapezoid a letter and a length: A, B, C and D for the four sides, plus E and F for clipped corners or end pieces, then add the depth and thickness.
- [The size menu only asks for width and length. What do I pick for a trapezoid cushion?](https://cushionguide.com/answers/trapezoid-cushion-size-selection-width-length/): Pick the size range that covers your trapezoid's longest side and its deepest depth; that choice only sets the price.
- [Measuring a 3-sided bay window seat cushion, panel by panel](https://cushionguide.com/guides/bay-window-seat-cushion-3-sided/)
- [How to order a custom cushion size that isn't in the size menu](https://cushionguide.com/guides/custom-size-cushion-not-on-menu/)

*± 1/4 in — Nate*

---

Written by Nate Kowalski (https://cushionguide.com/masters/nate/) for CushionGuide (https://cushionguide.com/about/). The site explains made-to-measure cushions and the partner workshop makes them; measurements are in inches first. This Markdown mirrors the page at https://cushionguide.com/readings/trapezoid-bay-window-cushion-top-down-view/