---
title: "Bay Window Cushion in Navy Stripe: Mistakes the Angle Avoids"
url: "https://cushionguide.com/readings/navy-stripe-angled-bay-window-seat-cushion/"
section: "Readings"
author: "Nate Kowalski, The Pattern Engineer of Detroit"
author_url: "https://cushionguide.com/masters/nate/"
published: "2026-06-02"
updated: "2026-09-24"
keywords: "bay window cushion, bay window seat cushion, angled window seat cushion, trapezoid bench cushion, striped bench cushion, custom window seat cushion"
---

# Navy stripe bay window cushion: the angled end, and five mistakes it avoided

*One end square, one end cut on the bay's angle, and a navy stripe that never breaks. Partner, that stripe is straight only because somebody measured the diagonals.*

> **The quick answer:** To order a bay window cushion with an angled end, send a drawing with every edge labeled, short straight returns included, and both diagonals measured, because old bays are rarely square. Angled seats go through the custom trapezoid option. Standard thickness is 4 in (10 cm); write anything thinner or thicker in the personalization box.

![Navy and white striped bay window seat cushion with an angled end, two ivory linen pillows and a fern on the sill](https://cushionguide.com/media/bay-window-cushions/navy-stripe-angled-bay-window-seat-cushion-1600.webp "The cushion follows the bay's angled side exactly, so the navy stripe runs unbroken from wall to wall.")

## What this page of the notebook shows

The photo is a white-paneled bay with brick row houses outside. On the seat, a navy and white ticking stripe, box edge, self piping. The left end is cut on the bay's angle instead of squared off, and that is why the stripe looks built in rather than bought.

The navy is a true dark blue. From across the room it reads almost black, so the white paneling does real work: it keeps a heavy color crisp.

Props, in order of usefulness. Two plain ivory linen pillows sit in the angled corner, exactly where a back rests against the splay. The fern on the sill is the only green, placed at the center so the eye travels the full stripe. The fringed cream throw folds at the square end to balance the pillows. Oak boards keep it warm.

The cloth is one of the [striped cotton and ticking](https://cushionguide.com/fabrics/striped-cotton-and-ticking/) family; more seats like it sit under [bay window cushions](https://cushionguide.com/cushions/bay-window-cushions/), and the [3-sided bay Pattern](https://cushionguide.com/guides/bay-window-seat-cushion-3-sided/) measures one panel by panel. How many edges does your bay actually have?

## Margin notes on the photo

Five points where the geometry and the styling agree.

1. **angled bay end**: The end is cut on the bay's angle; send a drawing with every edge labeled and both diagonals measured.
2. **ivory linen pillows**: Two plain pillows sit in the angled corner where a back naturally rests against the splay.
3. **fern on the sill**: The fern is the only green, placed centrally so the eye travels along the whole stripe.
4. **fringed cream throw**: The throw is folded at the square end, balancing the pillows piled at the angled end.
5. **navy stripe box edge**: This navy can read almost black from across the room, so white paneling keeps it crisp.

## Five mistakes this cushion avoided

- ✗ Squaring off the angled end. A rectangle on a canted bay leaves a triangle of bare wood you see every day.
- ✗ Skipping the short straight returns. Many bays have a small flat stretch before the angle starts; label it.
- ✗ Trusting the corners. Measure both diagonals; if they differ, the bay is not square.
- ✗ Mixing up depth and thickness. Depth runs front to back; thickness is the foam height.
- ✗ Leaving piping to chance. For a contrast cord, write both fabric codes in the order note.

## An L-shaped bay in three numbers

A buyer wrote in about an L-shaped bay seat: one leg 44 1/2 in (113 cm), the other 74 3/4 in (190 cm), 22 7/8 in (58 cm) deep. Three numbers, and the workshop could quote the whole piece.

That is the method for an L. Give the outer length of each leg along the wall, and one depth. The inside lengths follow from the depth, so measuring them again only adds a chance for two numbers to disagree. Run yours through the [bay window calculator](https://cushionguide.com/studio/bay-window-calculator/) before you order.

## Three questions

**A common question:** Our bay window seat has three sides and isn't a rectangle. Can you make a cushion for it?

**The workshop's answer:** Yes. Angled bay seats go through the custom trapezoid option: upload a photo and a drawing with measurements, and the cushion is shaped to match. Benches with wood sticking out are handled the same way.

**A common question:** What thickness is standard, and can I go thinner or thicker?

**The workshop's answer:** Standard is 4 in (10 cm). Thinner cushions have been made at 3 1/2, 3, 2 and even 1 in, thicker ones at 6 and 8 in. Write the thickness in the personalization box, for example "3 inches" on a trapezoid order.

**A common question:** Can the piping be a different color or fabric from the cushion?

**The workshop's answer:** Yes. Contrast piping can be any color on the fabric charts. Write both codes in the order note, main fabric and piping, and the workshop confirms them before production.

> **Tailor's margin:** A bay window cushion drawing needs every edge labeled and both diagonals measured. If the two diagonals differ, the bay is not square.

> For an L-shaped window seat, give the outer length of each leg and one depth. Three numbers describe the whole cushion.
>
> — Nate

## Spec sheet

|   |   |
|---|---|
| Cushion | Angled bay window seat cushion |
| Fabric | Navy and white ticking stripe (code N28) |
| Stripe | Unbroken wall to wall |
| Piping | Self piping |
| Edge | Box edge |
| Thickness | 4 in (10 cm) standard; 1 to 8 in on request |
| Ordering | Custom trapezoid option, photo plus drawing |
| Best for | Canted bays and L-shaped window seats |

## Questions buyers ask next

### Why measure the diagonals of a bay window seat?

Diagonals show whether the seat is square. When the two corner-to-corner figures differ, the angles are not what they look like, and a cushion cut from lengths alone will gap at one end.

### Where do pillows go on an angled bay seat?

In the angled corner, where a back naturally rests against the splay. Keep them plain when the cushion is striped, and fold a throw at the square end for balance.

### Will a navy stripe look black in my room?

From across a room, a deep navy can read almost black. Pale walls keep it crisp; in a darker room, ask for a daylight close-up of the fabric before ordering.

## Related at the atelier

- [Bay Window Cushion Set in Navy Floral, Cut in Three Pieces](https://cushionguide.com/readings/three-piece-navy-floral-bay-window-cushion-set/): A three-sided bay window cushion works best as three pieces: a center rectangle and two end pieces cut to each wall's angle, with the joins under the mullions.
- [Bay Window Cushion in Green Velvet: Five Mistakes It Avoids](https://cushionguide.com/readings/forest-green-velvet-self-piped-bay-seat-oak-sash/): The first mistake to avoid on a bay window cushion is a sketch with edge lengths but no front-to-back depth.
- [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.
- [Measuring a 3-sided bay window seat cushion, panel by panel](https://cushionguide.com/guides/bay-window-seat-cushion-3-sided/): Measure a 3-sided bay window seat cushion as a center panel plus two angled wings, taking every number from the trim face: the back edge of each panel, the full front edge, the depth at both ends of…
- [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.
- [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.
- [How to measure a trapezoid cushion so the numbers close](https://cushionguide.com/guides/trapezoid-cushion-measurements/)

*± 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/navy-stripe-angled-bay-window-seat-cushion/