Pricing sources checked October 27, 2026 · How we calculate
Preset: Window style: Bay / bow. Use the main calculator to change it.
One vinyl bay or bow unit with Low-E glass, replacing an existing bay on the ground floor, comes out at $1,500–$4,000 in this model. On an upper floor it's $1,680–$4,480, and in wood $2,550–$6,800.
What bay and bow windows cost in 2026
Most 2026 sources put a bay or bow window at roughly $1,700–$4,000 installed, with large or custom units running to $5,000–$7,000.
| Source | Bay | Bow |
|---|---|---|
| HomeAdvisor | $1,800–$4,000 (average $2,500) | $1,800–$4,000 |
| Modernize | $1,700–$3,859 or more (bay/bow) | (combined) |
| Angi | $900–$7,100 | $1,500–$6,500 |
| This Old House (bay guide) | $602 average unit; $1,125–$5,300 installed by bay type | $2,400–$5,300 installed |
By bay type and size (This Old House)
| Type | Installed cost |
|---|---|
| Box bay | $1,125–$1,350 |
| Canted bay | $1,500–$4,200 |
| Oriel | $1,600–$4,800 |
| Circle bay | $2,700–$4,800 |
| Bow | $2,400–$5,300 |
| Size | Installed cost |
|---|---|
| 4 × 3 ft | $700–$1,800 |
| 6 × 3 ft | $900–$3,500 |
| 8 × 3 ft | $950–$4,000 |
| 10 × 3 ft | $1,500–$7,000 |
This Old House notes its bay guide's figures come from contractor estimates used by Fixr and Angi (This Old House, June 2, 2026).
Bay vs. bow
A bay window typically has three panels, a large center window flanked by two angled side windows, and projects out from the wall. A bow window uses more panels set in a gentle curve: at least five, according to HomeAdvisor, and five to seven or more according to This Old House. More panels and a larger roof and seat make bows the pricier of the two in most sources.
What's extra on a bay window quote
- Structural support: This Old House notes the projecting design may need additional structural support. Ask how the unit will be supported (cables, brackets or a knee wall).
- Roof or cap: the small roof over the bay, including flashing to the wall, which matters most on a replacement
- Seat board and insulation: the interior seat, plus insulation under the projection, a common source of cold floors
- Interior trim and drywall where the old unit comes out
- Permits: often required when an opening changes, and almost always for a new bay
Replacing a flat window with a bay? That means enlarging or reframing the opening, so treat this calculator's range as the window portion only and get a structural quote. More detail: bay window installation cost on Window Cost Estimate.
Sources
- HomeAdvisor: What Is the Average Cost to Install Windows in 2026? (updated June 17, 2026; checked October 27, 2026).
- HomeAdvisor: How Much Does Window Replacement Cost in 2026? (updated June 17, 2026; checked October 27, 2026).
- Modernize: Window Replacement Cost Calculator (2026) (updated September 22, 2026; checked October 27, 2026).
- Angi: How Much Does Window Replacement Cost? [2026 Data] (updated October 15, 2026; checked October 27, 2026).
- This Old House: How Much Does a Bay Window Cost? (2026 Guide) (updated June 2, 2026; checked October 27, 2026).
- This Old House: Window Replacement Cost (2026 survey of 1,000 homeowners) (updated August 11, 2026; checked October 27, 2026).
Frequently asked questions
How much does a bay window replacement cost?
Most 2026 sources put it at about $1,700–$4,000 installed. HomeAdvisor gives an average of $2,500. Large, wood or custom units, and new openings, can run higher.
Are bow windows more expensive than bay windows?
Usually. Bows have more panels and a wider projection. This Old House puts bows at $2,400–$5,300 installed, against $1,125–$4,800 for most bay types.
Does the calculator include structural work?
No. The bay/bow range assumes you're replacing an existing projecting unit. Creating a new bay opening, reframing or adding support is priced separately.
Is a bay window cheaper on the ground floor?
Yes. Upper-floor units need staging and more support, and this model adds 12%. Oriel (upper-floor) bays in This Old House's guide run $1,600–$4,800 installed.