Bay Window Types Explained: Bay, Bow and Walk-In Windows
22nd July 2026
Bay-window terminology can be confusing because some names describe the shape of the window, while others describe the space it creates inside the room.
This guide explains the main differences so you can quickly understand which type of window you have, or which style may suit your home.
The key difference
Bay, bow, canted and box describe the shape of the window. Walk-in describes whether the floor continues into the bay.
This means a window can be both a walk-in bay and a canted bay at the same time.
Bay window shapes at a glance
A flat front window with two angled sides. This is the familiar three-sided bay seen on many British homes.
A square or rectangular bay with side windows positioned at, or close to, right angles.
Several window sections arranged at shallow angles to create a softer, curved appearance.
What is a walk-in bay?
A walk-in bay is a bay where the room’s floor extends into the projected area. You can physically step into it, rather than reaching across a deep sill or window board.
A walk-in bay can be canted, square or curved. The term describes the inside of the room, not the outside shape.
Which type is right for you?
| Window type | Best known for | Space inside |
|---|---|---|
| Canted bay | A traditional angled appearance | Depends on the existing structure |
| Box bay | A square, practical shape | Can provide useful floor space |
| Bow window | A softer curve and panoramic view | Often creates a deeper sill rather than floor space |
| Walk-in bay | Additional usable room | The floor continues into the bay |
Main advantages and considerations
Bay and canted windows
Advantages:
- Allow light to enter from several directions.
- Create a strong architectural feature.
- Provide wider views than a flat window.
Considerations:
- Blinds and curtains may need to follow the angles.
- The roof, base and supporting structure should be assessed.
- The number of frame sections can affect the view.
Bow windows
Advantages:
- Create a softer, curved appearance.
- Provide a broad, panoramic outlook.
- Can add character to a flat frontage.
Considerations:
- They do not always create usable floor space.
- They use several separate window sections.
- Made-to-measure window coverings may be needed.
Walk-in bays
Advantages:
- Create genuine usable space inside the room.
- Can accommodate seating, furniture or a small desk.
- Make the bay feel like part of the room.
Considerations:
- A new walk-in bay may involve structural work.
- Flooring, insulation, roofing and ventilation must be considered.
- Permission may be needed when creating a new projection.
Other terms you may hear
What is a standard bay?
“Standard bay” is an informal term. It often means a traditional three-section angled bay, but it can also simply refer to an existing bay being fitted with replacement windows. It is always worth checking the proposed shape and internal layout.
What is an oriel bay?
An oriel bay projects from an upper floor without continuing down to ground level. It is usually supported from beneath.
What is a multi-sided bay?
A multi-sided or polygonal bay uses several straight window sections to create a broader or more rounded shape.
Frequently asked questions
Is a bow window the same as a bay window?
A bow window is a type of projecting window, but it has a softer curved appearance. A traditional bay usually has more clearly defined angles.
Is every bay window walk-in?
No. Some bays have a deep sill or window board rather than floor space that you can step into.
Can a bow window also be walk-in?
Yes, potentially. Bow describes the curved shape, while walk-in describes the internal floor arrangement.
Which type lets in the most light?
Both bay and bow windows can bring in light from several directions. The result depends on the total glazed area, frame design, orientation and nearby obstructions.
Do bay windows need planning permission?
Replacing windows within an existing bay will not usually require a planning application. Creating a new projecting bay may require permission, especially at the front of a property. Listed buildings, conservation areas and structural alterations may also have additional requirements.
Choosing the right bay window
The right option depends on the style of your property, the existing structure and whether your priority is more light, a wider view or usable floor space.
A survey allows the bay roof, base, supports, dimensions and opening arrangement to be checked before the final design is agreed.
Not sure which type of bay window you have?
Visit an EYG showroom or arrange a home survey to discuss the available options.
