Egress Window Calculator 2026 — Size Check & Cost
Check a basement egress window against IRC R310 (5.7 sq ft, 24 in high, 20 in wide, 44 in sill) and price it. Typical cost: $2,621–$5,662 per window.
Egress Window Size & Cost Calculator
1. Does the opening meet IRC R310?
Measure the clear opening with the sash fully open, not the frame or the rough opening.
Side to side, inside the open sash. Minimum 20 in.
Bottom to top of the open space. Minimum 24 in.
Finished floor to the bottom of the clear opening. Maximum 44 in.
Out from the wall. Min 36 in.
Along the wall. Min 36 in.
Ground to well floor. Over 44 in needs a ladder.
Meets the IRC R310 minimums Net clear opening 6.00 sq ft
- Net clear opening area R310.2.1: at least 5.7 sq ft6.00 sq ft (24 × 36 in)OK
- Net clear opening height R310.2.2: at least 24 in36 inOK
- Net clear opening width R310.2.2: at least 20 in24 inOK
- Sill height above the floor R310.2.3: no more than 44 in40 inOK
- Window well floor area R310.4.1: at least 9 sq ft10.00 sq ftOK
- Well projection from the wall R310.4.1: at least 36 in36 inOK
- Well width R310.4.1: at least 36 in40 inOK
- Ladder or steps in the well R310.4.2: required when the well is deeper than 44 in48 in deep: ladder or steps requiredOK
2021 International Residential Code minimums. Your city or county may have adopted a different edition or local amendments; confirm with the building department before you order the window.
2. What will it cost?
A ladder is added when a standard well is deeper than 44 in.
Adjusts the labor share by local construction wages (BLS, May 2025).
homeprojectestimator.com · · https://homeprojectestimator.com/calculators/egress-window-cost/
Estimated egress window cost (one window)
$5,350
Typical range $1,950 – $8,750
Where the money goes
- Casement egress window (unit only) $200 – $500
- Setting, flashing and trimming the window $100 – $1,000
- Cut a new opening in the concrete or block foundation $700 – $3,000
- Excavation for the window well $500 – $2,000
- Window well with cover (corrugated steel or plastic) $200 – $1,500
- Well ladder (well deeper than 44 in) $150 – $250
- Building permit and inspection $100 – $500
National average. Pick your state and metro area to adjust the labor share (about 50% of this job) to local wages. Get three written quotes before you commit to a budget.
Line items from Fixr (August 2025), Block Renovation (April 2026), Bob Vila (January 2024) and This Old House. No source splits labor from materials for this job, so the state adjustment assumes labor is half the cost. Not included: structural engineering, interior drywall and trim around the new opening, and landscaping.
How to use this calculator
The tool has two parts. The first checks whether a window, existing or planned, meets the size rules in the International Residential Code. The second prices one installed basement egress window.
Part 1 — size check. Open the window as far as it normally opens and measure the clear space a person would climb through:
- Net clear width — side to side between the sash and the frame, not the frame's outside size. A casement that swings fully open gives most of its frame width; a slider gives much less, because the fixed panel stays in the way.
- Net clear height — bottom to top of the open space. On a double-hung window it is well under the frame height, because the lower sash slides up behind the upper one.
- Sill height — from the finished floor to the bottom of the clear opening.
- Grade-floor opening — tick this only if your building department treats the window as a grade-floor opening; it lowers the minimum area from 5.7 to 5.0 sq ft.
- Window well — if the sill is below the ground outside, enter how far the well projects from the wall, its width along the wall, and its depth from the ground to the well floor.
The result lists every rule with its section number and marks each one OK or Fails.
Part 2 — cost. Choose whether you are cutting a new opening or enlarging an existing basement window, the window style and the well type, and whether the well drain will be tied into the foundation drainage and a permit pulled. The ladder line appears on its own when a standard well is deeper than 44 inches, and the excavation, well and drain lines drop out if the sill is above grade.
Egress window size requirements (IRC R310)
| Rule | 2021 IRC section | Requirement |
|---|---|---|
| Where required | R310.1 | Basements and every sleeping room: at least one operable emergency escape and rescue opening |
| Operation | R310.1.1 | Opens from inside without keys, tools or special knowledge |
| Net clear opening area | R310.2.1 | At least 5.7 sq ft; grade-floor openings at least 5 sq ft |
| Net clear height | R310.2.2 | At least 24 in |
| Net clear width | R310.2.2 | At least 20 in |
| Sill height | R310.2.3 | Bottom of the clear opening no more than 44 in above the floor |
| Under a deck or porch | R310.2.4 | Fully openable, with a path at least 36 in high to a yard or court |
| Window (area) well size | R310.4.1 | At least 9 sq ft, with at least 36 in projection and 36 in width |
| Ladder or steps | R310.4.2 | Required when the well is deeper than 44 in |
| Ladder rungs | R310.4.2.1 | At least 12 in wide, project at least 3 in, no more than 18 in apart |
| Drainage | R310.4.3 | Connected to the foundation drainage, except on well-drained soils |
| Covers, bars, grilles | R310.4.4 | Releasable or removable from inside without a key or tool |
Source: International Code Council, 2021 International Residential Code, Section R310, as quoted by Boulder County Community Planning & Permitting, Emergency Escape and Rescue Openings - B10.
The area rule catches most people out, because the two minimum dimensions do not add up to it: 24 × 20 inches is 480 sq in, or 3.3 sq ft. To reach 5.7 sq ft (820.8 sq in), a 20-inch-wide opening needs about 41 inches of height, and a 24-inch-tall opening needs about 34.2 inches of width. At the 5.0 sq ft grade-floor minimum, those become 36 inches and 30 inches.
Local codes differ. Cities and counties adopt a particular IRC edition and amend it. Boise's 2022 egress handout, written on an earlier edition, still allows 5 sq ft for below-grade openings, exempts basements used only for mechanical equipment up to 200 sq ft, and lets a replacement window skip the size and sill rules if it is the largest standard size that fits the existing opening. Boulder County adds a requirement for a licensed design professional on foundation cuts. Treat the table as the model code and confirm with your building department before you order the window.
Egress window cost in 2026
| Source | Typical cost per window |
|---|---|
| Angi data via Bob Vila (January 2024) | $2,621 – $5,662, average $4,129 |
| Fixr, prefab, basement (August 2025) | $2,500 – $5,000, average $3,500 |
| Fixr, custom, basement (August 2025) | $3,000 – $7,500 |
| Block Renovation (April 2026) | $2,700 – $6,000+ |
Sources: Bob Vila, How Much Does an Egress Window Cost to Install?, January 21, 2024; Fixr, Cost to Install an Egress Window, August 29, 2025; Block Renovation, Basement Egress Window Installation: Cost, Code Requirements & Design Ideas, April 28, 2026.
The line items the calculator uses:
| Item | Cost | Source |
|---|---|---|
| Window unit, prefab (materials only) | Single-hung $100–$400, sliding $150–$700, casement $200–$500, double-hung $250–$500 | Fixr, Aug 2025 |
| Setting the window (labor) | $100 – $1,000 | Bob Vila, Jan 2024; Block Renovation, Apr 2026 |
| Cut a new opening in the foundation | $700 – $3,000 | about $700: Bob Vila; $1,500–$3,000: Block Renovation |
| Enlarge an existing opening | $150 – $200 | Fixr; This Old House; Bob Vila |
| Excavation | $500 – $2,000 | Block Renovation, Apr 2026 |
| Window well with cover | $200 – $1,500 | Block Renovation, Apr 2026 |
| Molded well with built-in steps (Bilco ScapeWEL 2-tier, 66 in) | $2,590 retail | Industrial Supplies listing, Oct 2026 |
| Well ladder | $150 – $225 | Fixr, Aug 2025 |
| Drain tie-in | $500 – $2,000 | Block Renovation, Apr 2026 |
| Permit and inspection | $100 – $500 | This Old House; Block Renovation |
Sources disagree on excavation more than anything else. Block Renovation puts it at $500–$2,000; This Old House says $3,000–$7,000 including the labor to install the well; Bob Vila prices digging at $50–$200 per cubic yard, with most windows needing 1 to 1.5 cubic yards. The calculator uses Block Renovation's figure because it is the only one that prices excavation as its own line next to the other items.
For the defaults — a new cut, a casement, a standard well 48 inches deep with a ladder, a permit, no drain tie-in — the estimate is $1,950 to $8,750, typically $5,350, inside the Angi range.
What drives the price
- New cut or enlargement. Cutting a new opening ($700–$3,000) against enlarging an existing one ($150–$200) is the biggest single choice. In the calculator, enlarging brings the typical estimate down to $3,700.
- Poured concrete or block. Block Renovation says block foundations are the easiest and cheapest to cut, while poured concrete adds labor time. One basement contractor, Acculevel, published complete egress prices in 2021 of $8,000–$8,200 in block and $8,400–$8,600 in poured concrete with machine digging.
- Digging access. The same contractor charged $9,200–$9,700 when the well had to be dug by hand to protect landscaping.
- Well type. A basic well with cover runs $200–$1,500; a molded two-tier well with built-in steps costs $2,590 retail and replaces the ladder, raising the typical estimate to $6,900.
- Drainage. A tie-in to the foundation drain adds $500–$2,000 and lifts the typical estimate to $6,600. R310.4.3 waives it only on well-drained soils.
- Number of windows. This Old House notes that installing several egress windows at once saves on labor.
Cost breakdown
The estimate always includes the window unit, the labor to set it and the work on the foundation opening. Below-grade openings add excavation and the well, a ladder when a standard well is deeper than 44 inches, and the drain tie-in if ticked. The permit line is on by default.
Not included: an engineer's letter or stamped design where your jurisdiction requires one, interior drywall, trim and paint around the new opening, lawn and landscaping repair, and a well cover upgrade — Fixr prices covers at $120–$700 and Block Renovation prices clear polycarbonate covers at $50–$300.
Prices by state and metro area
The state selector scales only the labor share: (1 − labor share) + labor share × the state's construction wage index, the state mean hourly wage for construction and extraction occupations over the national $31.42 (BLS OEWS, May 2025). No source splits egress window cost into labor and materials, so the calculator assumes labor is half.
For the default estimate ($5,350 national):
- Illinois (index 1.25): about $6,000
- Texas (index 0.84): about $4,900
- Arkansas (index 0.74): about $4,650
Metro areas spread wider than states. With the default settings, this estimate is $5,350 at the national average, $6,050 in the New York-Newark-Jersey City, NY-NJ metro area and $4,950 in Tampa-St. Petersburg-Clearwater, FL (BLS construction wage index 1.26 and 0.85). Pick your metro area under the state to use the local figure.
Choosing the window
Casements give the most clear opening for their frame size because the whole sash swings out, which is why they are the default here; a slider or double-hung opens only part of its frame, so it must be considerably larger to reach 5.7 sq ft. Whatever the style, check the manufacturer's stated net clear opening against the table above before ordering, and remember that a window well cover, grille or bar must release from inside without a key or tool (R310.4.4).
DIY or hire out?
The expensive, risky part is the foundation cut. This Old House describes contractors cutting the opening with a concrete saw from both the inside and the outside, and Boulder County requires a licensed design professional to design or inspect foundation wall cuts. Setting a window into an opening that already meets the size rules is ordinary carpentry; cutting a structural wall, digging the well and tying in drainage are jobs for a contractor who does egress windows regularly. Whoever does the work, the permit and final inspection are your record that the opening meets code when you sell.
Sources
- Boulder County Community Planning & Permitting, Emergency Escape and Rescue Openings - B10 — text of 2021 IRC Section R310: R310.1–R310.4.4 (accessed October 29, 2026). link
- City of Boise, IRC Code Handout #438: Emergency Escape & Rescue Openings — local wording on below-grade openings, exceptions and replacement windows (March 2022). link
- Fixr, Cost to Install an Egress Window — basement price ranges, window units by style, enlarging an opening, ladder, cover, permits (updated August 29, 2025). link
- Bob Vila, How Much Does an Egress Window Cost to Install? — national range and average from Angi, cutting and resizing an opening, excavation, labor, permits (updated January 21, 2024). link
- Block Renovation, Basement Egress Window Installation: Cost, Code Requirements & Design Ideas — foundation cutting, excavation, well, cover, drainage, permits, labor (April 28, 2026). link
- This Old House, Egress Window Cost — enlarging an opening, excavation, permits, multiple windows (accessed October 29, 2026). link
- Acculevel, How Much Do Egress Windows Cost? — complete prices for block vs poured walls and machine vs hand digging (June 18, 2021). link
- Industrial Supplies, Bilco WW4048-66 ScapeWEL 2 Tier Window Well Two Part Package — retail price (accessed October 29, 2026). link
- U.S. Bureau of Labor Statistics, Occupational Employment and Wage Statistics — state construction wages behind the state selector (May 2025). link
Related
Frequently Asked Questions
What size does a basement egress window need to be?
Under the 2021 International Residential Code, the net clear opening must be at least 5.7 sq ft (R310.2.1), at least 24 inches high and 20 inches wide (R310.2.2), with the bottom of the opening no more than 44 inches above the floor (R310.2.3). Both minimums together are not enough: 24 × 20 inches is only 3.3 sq ft, so at 20 inches wide you need about 41 inches of height.
How much does a basement egress window cost?
Angi data quoted by Bob Vila puts the typical range at $2,621 to $5,662, with a national average of $4,129. Fixr lists $2,500 to $5,000 for a prefab below-ground egress window and $3,000 to $7,500 for a custom one (August 2025). Block Renovation puts most homeowners at $2,700 to $6,000 per window (April 2026). Cutting a new opening and digging the well are the big lines.
How big does an egress window well have to be?
IRC R310.4.1 requires a well floor of at least 9 sq ft, with at least 36 inches of projection out from the wall and 36 inches of width, and the window must be able to open fully inside it. A well deeper than 44 inches needs a permanently attached ladder or steps (R310.4.2), with ladder rungs at least 12 inches wide and no more than 18 inches apart.
Is it cheaper to enlarge an existing basement window?
Usually. Fixr, This Old House and Bob Vila all put enlarging a window opening at $150 to $200, while cutting a new opening runs about $700 according to Bob Vila and $1,500 to $3,000 for foundation cutting according to Block Renovation. You still pay for excavation, the well and the window, so in this calculator enlarging saves about $1,650 on the typical estimate.
Do I need a permit for an egress window?
Almost always, because the job cuts a structural foundation wall. This Old House and Block Renovation put permit fees at $100 to $500, and Block Renovation gives $150 to $800 for permits and inspections together; Fixr says most permits cost about $50 to $200. Some jurisdictions want more: Boulder County requires foundation wall cuts to be designed or inspected by a Colorado-licensed design professional.
Does a basement bedroom need its own egress window?
Yes. IRC R310.1 says basements and every sleeping room must have at least one operable emergency escape and rescue opening, so each basement bedroom needs its own window or door that meets R310. The opening must work from inside without keys, tools or special knowledge (R310.1.1). Some code text, such as the version in Boise's 2022 handout, exempts basement bedrooms in fully sprinklered houses that have the required exits.