Window Replacement Cost Calculator & Estimator
Enter up to 3 window groups and quote rates to compare united-inch pricing against flat per-window bids. The 7 default windows (660 UI) total $3,102.00 installed.
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Estimated window replacement cost
Estimated Total
$3,102.00
Window Cost
$2,052.00
Installation
$1,050.00
7 windows (660 UI, 104 sq ft in 3 groups) at $3.00 per UI plus $150.00 labor per unit cost $3,102.00, or $443.14 each ($29.83/sq ft).
Units cost $2,052.00 ($3.11 per united inch after style factors) and labor adds $1,050.00.
The section 25C window credit ended for windows placed in service after December 31, 2025, so no credit is taken off this total.
Change the inputs
- United inches = 4 × (36 + 60) + 2 × (30 + 48) + 1 × (72 + 48) = 660
- Window cost = 4 × $288.00 + 2 × $234.00 + 1 × $432.00 = $2,052.00
- Installation = 7 × $150.00 = $1,050.00
- Estimated total = $2,052.00 + $1,050.00 = $3,102.00
Window and installation cost by size group
Installed total across the example quote rates
Estimated total at different prices per united inch
Across the 10 sample united-inch rates from $2.00 to $8.00, the installed project total moves from $2,418.00 ($345.43 per window) to $6,522.00 ($931.71 per window).
| Price per united inch | Window cost | Installation | Estimated total | Per window, installed |
|---|---|---|---|---|
| $2 | $1,368.00 | $1,050.00 | $2,418.00 | $345.43 |
| $2.5 | $1,710.00 | $1,050.00 | $2,760.00 | $394.29 |
| $3 (closest to your input) | $2,052.00 | $1,050.00 | $3,102.00 | $443.14 |
| $3.5 | $2,394.00 | $1,050.00 | $3,444.00 | $492.00 |
| $4 | $2,736.00 | $1,050.00 | $3,786.00 | $540.86 |
| $4.5 | $3,078.00 | $1,050.00 | $4,128.00 | $589.71 |
| $5 | $3,420.00 | $1,050.00 | $4,470.00 | $638.57 |
| $6 | $4,104.00 | $1,050.00 | $5,154.00 | $736.29 |
| $7 | $4,788.00 | $1,050.00 | $5,838.00 | $834.00 |
| $8 | $5,472.00 | $1,050.00 | $6,522.00 | $931.71 |
Estimated total, by price per united inch (down) and installation per opening (across), with every other input as entered above.
| Price per United Inch by installation per opening | $100 | $150 | $200 | $300 | $400 |
|---|---|---|---|---|---|
| $2 | $2,068.00 | $2,418.00 | $2,768.00 | $3,468.00 | $4,168.00 |
| $2.5 | $2,410.00 | $2,760.00 | $3,110.00 | $3,810.00 | $4,510.00 |
| $3 (closest to your input) | $2,752.00 | $3,102.00 | $3,452.00 | $4,152.00 | $4,852.00 |
| $3.5 | $3,094.00 | $3,444.00 | $3,794.00 | $4,494.00 | $5,194.00 |
| $4 | $3,436.00 | $3,786.00 | $4,136.00 | $4,836.00 | $5,536.00 |
| $4.5 | $3,778.00 | $4,128.00 | $4,478.00 | $5,178.00 | $5,878.00 |
| $5 | $4,120.00 | $4,470.00 | $4,820.00 | $5,520.00 | $6,220.00 |
| $6 | $4,804.00 | $5,154.00 | $5,504.00 | $6,204.00 | $6,904.00 |
| $7 | $5,488.00 | $5,838.00 | $6,188.00 | $6,888.00 | $7,588.00 |
| $8 | $6,172.00 | $6,522.00 | $6,872.00 | $7,572.00 | $8,272.00 |
Estimated total at different installation prices
Varying installation labor from $0.00 (material-only) to $500.00 per opening moves the total from $2,052.00 to $5,552.00 ($793.14 per window).
| Installation per opening | Installation, all openings | Estimated total | Per window, installed |
|---|---|---|---|
| $0 | $0.00 | $2,052.00 | $293.14 |
| $100 | $700.00 | $2,752.00 | $393.14 |
| $150 (closest to your input) | $1,050.00 | $3,102.00 | $443.14 |
| $200 | $1,400.00 | $3,452.00 | $493.14 |
| $250 | $1,750.00 | $3,802.00 | $543.14 |
| $300 | $2,100.00 | $4,152.00 | $593.14 |
| $400 | $2,800.00 | $4,852.00 | $693.14 |
| $500 | $3,500.00 | $5,552.00 | $793.14 |
By window size
| Size | Windows | Width × height | UI each | UI total | Glass area (sq ft) | Style factor | Window cost | Installation | Installed total | Installed per sq ft |
|---|---|---|---|---|---|---|---|---|---|---|
| Size 1 | 4 | 36 × 60 in | 96 | 384 | 60 | 1 | $1,152.00 | $600.00 | $1,752.00 | $29.20 |
| Size 2 | 2 | 30 × 48 in | 78 | 156 | 20 | 1 | $468.00 | $300.00 | $768.00 | $38.40 |
| Size 3 | 1 | 72 × 48 in | 120 | 120 | 24 | 1.2 | $432.00 | $150.00 | $582.00 | $24.25 |
Across 7 openings (104 sq ft total glass area), Size 2 (30 × 48 in) has the highest installed rate at $38.40 per sq ft, while Size 3 (72 × 48 in) drops to $24.25 per sq ft.
Example quote rates compared (the page's own illustrative rates)
| Quote basis | Window cost | Installation | Installed total | Per window, installed | Installed per sq ft |
|---|---|---|---|---|---|
| $2.50/UI | $1,710.00 | $1,050.00 | $2,760.00 | $394.29 | $26.54 |
| $3.00/UI | $2,052.00 | $1,050.00 | $3,102.00 | $443.14 | $29.83 |
| $3.50/UI | $2,394.00 | $1,050.00 | $3,444.00 | $492.00 | $33.12 |
| $4.50/UI | $3,078.00 | $1,050.00 | $4,128.00 | $589.71 | $39.69 |
| $6.00/UI | $4,104.00 | $1,050.00 | $5,154.00 | $736.29 | $49.56 |
| $8.00/UI | $5,472.00 | $1,050.00 | $6,522.00 | $931.71 | $62.71 |
| $450.00/window | $3,240.00 | $1,050.00 | $4,290.00 | $612.86 | $41.25 |
| $650.00/window | $4,680.00 | $1,050.00 | $5,730.00 | $818.57 | $55.10 |
These eight rates are examples chosen for this page, not market data. For your 7 openings, installed project cost runs from $2,760.00 at $2.50/UI to $6,522.00 at $8.00/UI. It is $4,290.00 at $450.00 flat per window and $5,730.00 at $650.00 flat. No tax credit is taken off.
How it works
Dealers price custom units by united inches (UI). UI is width plus height in inches. A 36 × 60 in unit is 96 UI (15 sq ft), a 30 × 48 in is 78 UI (10 sq ft), and a 72 × 48 in is 120 UI (24 sq ft).
Per-UI mode multiplies UI by your UI rate, factor, and count. Per-window mode multiplies flat price by factor and count. Breakeven is flat price ÷ UI rate: 450 ÷ 3 = 150 UI, unchanged at 1.2× because the factor scales both prices.
Small units cost more per sq ft since $150.00 labor splits over fewer sq ft. A 36 × 60 in unit ($438.00, 15 sq ft) is $29.20/sq ft. The 7-window default job is $29.83/sq ft installed.
ENERGY STAR Version 7.0 zones, DOE cost benchmarks, and the 25C credit that ended
Your own contractor quote sets every price in the result. The quote table uses example rates chosen for this page: $2.50 to $8.00 per united inch and flat prices of $450.00 and $650.00. They are not market data. U.S. DOE Building America Table 44 reports installed replacement costs, in 2012 dollars, of $24 per sq ft for clear double-pane nonmetal units. Low-e double-pane units average $29 per sq ft, and low-e triple-pane units average $34 per sq ft. That includes $3 per sq ft for demolition over new-build costs of $21, $26, and $31 per sq ft. High-performance replacement units run $25 to $30 per sq ft for double-pane and $35 per sq ft or more for triple-pane. Top new-build units reach $40 to $60 per sq ft. Those 2012 averages are not 2026 prices.
ENERGY STAR Version 7.0 Section 3 (Table 1) took effect on October 23, 2023. It sets maximum U-factors and solar heat gain coefficients (SHGC) across four U.S. climate zones. The Northern zone sets U-factor <= 0.22 with SHGC >= 0.17 (or up to 0.26 if SHGC >= 0.40 in Table 4). The North-Central zone sets U-factor <= 0.25 and SHGC <= 0.40. The South-Central zone sets U-factor <= 0.28 and SHGC <= 0.23. The Southern zone sets U-factor <= 0.32 and SHGC <= 0.23. Table 5 limits air leakage to 0.3 cfm/sq ft for every window in every zone.
The federal section 25C credit for windows has ended. Under 26 U.S.C. 25C(i), the section "shall not apply with respect to any property placed in service after December 31, 2025." The 2025 IRS Form 5695 instructions agree: you can't claim energy efficient home improvement credits for expenditures or property placed in service after that date. A window placed in service in 2026 earns no credit under section 25C, so the totals on this page have no credit taken out.
Pre-1978 EPA lead-safe work and IRC egress and safety-glazing codes
Homes built before 1978 fall under 40 CFR Part 745 lead-paint rules. The EPA Lead Renovation, Repair and Painting Program page notes that about three-quarters of pre-1978 U.S. homes have lead paint. Under 40 CFR 745.80 and 745.82, paid firms in pre-1978 homes must be certified and use trained renovators. Under 40 CFR 745.82(a)(1) and (2), a job is exempt if a certified inspector, risk assessor, or renovator test kit finds the parts free of lead at or above 1.0 mg/cm² or 0.5% by weight. Owners doing DIY work in their own non-rental, non-childcare, non-flip home are also exempt. Under 40 CFR 745.83, minor work (6 sq ft or less inside or 20 sq ft or less outside) is exempt only "where the work does not involve window replacement or demolition of painted surface areas." Paid firms must give owners the lead pamphlet within 60 days before starting (40 CFR 745.84) and follow 40 CFR 745.85 work rules.
Section R310.2 of the 2018 Seattle Residential Code (printing the International Residential Code, IRC) sets minimum dimensions for emergency escape and rescue openings. Your jurisdiction may adopt a different edition or change these figures, so confirm with your building department. Each escape opening needs at least 5.7 sq ft of net clear area (or 5 sq ft at grade floor). Clear height must be at least 24 inches, and clear width must be at least 20 inches. The sill can sit no more than 44 inches above the floor. Under Section R310.2.5, a new window is exempt from these sizes if it is the maker's largest standard unit that fits the old frame or rough opening. It must also keep the same style or leave an equal or larger clear opening. Finally, the job cannot be part of a change of occupancy.
Safety glass is required in hazardous spots under IRC Section R308.4. Under IRC Section R308.4.3, a pane needs safety glass tested to CPSC 16 CFR 1201 (R308.3.1) when four rules all hold. The pane area is over 9 sq ft, and the bottom edge is under 18 inches above the floor. Also, the top edge is over 36 inches above the floor, and a walkway sits within 36 inches. Under R308.4.2, glass next to a door is also hazardous when its bottom edge is under 60 inches above the floor. That holds within 24 inches of either side of the door in the plane of the door. It also holds within 24 inches of the hinge side of an in-swinging door on a wall less than 180 degrees from the door's plane. If your quote adds a tempered-glass fee (such as an illustrative 1.2× factor), enter that factor in the Style Factor field.
Formula
UI each = width + height (united inches, with width and height in inches) window cost (per-UI mode) = Σ count × round(UI each × $/UI × style factor) window cost (per-window mode) = Σ count × round($/window × style factor) glass area (sq ft) = Σ count × (width × height) ÷ 144 installation = windows × install per opening estimated total = window cost + installation average per window = estimated total ÷ windows, where count is openings in a group, $/UI is price per united inch ($/in), $/window is flat price per unit ($), and style factor is the unit multiplier (×)
Example
Take 7 units at $3.00/UI and $150.00 labor: four 36 × 60 in (96 UI, $288.00), two 30 × 48 in (78 UI, $234.00), and one 72 × 48 in (120 UI, $360.00 base or $432.00 at 1.2×). They total 660 UI (104 sq ft, 110 ft).
Units cost $1,152.00 + $468.00 + $432.00 = $2,052.00 ($293.14 each, $3.11/UI), and labor adds $1,050.00 for $3,102.00 ($443.14 each). At $2.00/UI it is $2,418.00, and at $5.00/UI it is $4,470.00. At $450.00 flat, units cost $3,240.00 ($4,290.00 total, $1,188.00 more) below 150 united inches.
A window placed in service in 2026 gets no section 25C credit, so the $3,102.00 total is also the net cost.
Assumptions and limitations
- All rates, factors, and labor fees come from your quote. The defaults ($3.00/UI, $450.00/window, $150.00 labor) are example figures for this page, not market data. They give $29.83/sq ft installed.
- Per-UI unit price rounds to the nearest cent from (width + height) × $/UI × factor. Count multiplies that price.
- Glass area is (width × height) ÷ 144 sq ft. Perimeter is 2 × (width + height) ÷ 12 ft.
- Flat labor covers pocket inserts. Add framing, sill repair, permits, and pre-1978 EPA lead fees into labor if billed separately.
What to do with the result
Split units from labor on the bid so you can compare unit prices between dealers. Labor is $1,050.00, or 33.8% of the $3,102.00 default total.
Confirm 5.7 sq ft clear area (5 sq ft at grade), 24 × 20 in min opening, and 44 in sill on the egress window tool. Check the framing hole on the rough opening calculator.
Check your zone's U-factor, SHGC, and <= 0.3 cfm/sq ft air leakage on the window solar heat gain tool before paying $5/sq ft extra for triple-pane.
For 7 openings (110 ft), size trim on the door and window casing tool. The link fills in the count and size only when every window is one size. Count caulk on the caulk calculator and paint on the trim paint calculator.
Frequently asked questions
How do you calculate united inches and flat-rate breakeven?
Add width and height in inches: 36 × 60 in is 96 UI, 30 × 48 in is 78 UI, and 72 × 48 in is 120 UI. Breakeven is $450.00 ÷ $3.00 = 150 UI, unchanged at 1.2× because the factor scales both prices. Below 150 UI, per-UI pricing saves $162.00 on a 96 UI unit ($288.00 vs $450.00) and $1,188.00 on 7 units.
Why do smaller windows cost more per square foot?
UI grows with width plus height, while area grows with width times height, and $150.00 labor splits over fewer sq ft. A 30 × 48 in unit (78 UI, 10 sq ft) is $384.00 installed, or $38.40/sq ft. The 72 × 48 in unit (120 UI, 24 sq ft at 1.2×) is $582.00 installed, or $24.25/sq ft ($14.15/sq ft or 36.8% less).
Can I still claim the 25C tax credit for new windows?
Not for windows placed in service after December 31, 2025. Under 26 U.S.C. 25C(i) the section does not apply to property placed in service after that date. The 2025 IRS Form 5695 instructions say you can't claim energy efficient home improvement credits for it. A 2026 install gets no credit, so the totals on this page have none taken out.
How does 40 CFR 745.82 (the pre-1978 EPA lead rule) affect window replacement cost?
Under 40 CFR 745.82, paid work in pre-1978 homes falls under the EPA RRP Rule unless a certified inspector, risk assessor, or renovator test kit proves parts are lead-free under 40 CFR 745.82(a)(1)–(2). Unpaid DIY work by an owner in a non-rental, non-childcare, non-flip home is also exempt. Otherwise, Section 745.83 states that minor repair exclusions apply only where work does not involve window replacement. Paid firms must be certified, use trained renovators, give the lead pamphlet within 60 days, and follow lead-safe rules.
When does IRC Section R308.4 require safety glass in a window?
Under IRC Section R308.4.3 (2018 text, Seattle printing; your jurisdiction may differ), a pane needs safety glass when four conditions hold. Area is over 9 sq ft, bottom edge is under 18 in, top edge is over 36 in, and a walkway is within 36 in. Under R308.4.2, glass next to a door with a bottom edge under 60 in above the floor is also hazardous. That holds within 24 in of either side of the door, or within 24 in of the hinge side of an in-swinging door.
How long do ENERGY STAR windows take to pay back?
It depends on your own energy bill, your old windows and how many you replace. The ENERGY STAR Residential Windows, Doors, & Skylights page reports average savings of up to 13 percent nationwide when replacing single-pane windows. ENERGY STAR's Average Annual Energy Savings When Replacing Windows sheet (modelled for a 2,376 sq ft home) lists 11 to 12 percent ($493 to $568/yr) over single-pane and 6 to 8 percent ($253 to $373/yr) over clear double-pane. Payback is installed cost divided by yearly saving. As arithmetic only, an assumed saving of $260.00 a year repays $3,102.00 in 11.9 years. At $130.00 a year it takes 23.9 years, and at $100.00 a year it takes 31.0 years.
Sources
- ENERGY STAR, Residential Windows, Doors, & Skylights (current version)
- ENERGY STAR, Program Requirements for Residential Windows, Doors, and Skylights, Version 7.0 (current version)
- ENERGY STAR, Average Annual Energy Savings When Replacing Windows (current version)
- U.S. Department of Energy Building America, Measure Guideline: Energy-Efficient Window Performance and Selection (current version)
- EPA, Lead Renovation, Repair and Painting Program (page modified Jun 17, 2026)
- 40 CFR Part 745, Subpart E, Residential Property Renovation (GovInfo 2024 CFR) (current version)
- 26 U.S.C. 25C, Energy efficient home improvement credit (Cornell LII text) (current version)
- IRS, Instructions for Form 5695, Residential Energy Credits (2025) (form dated Jan 22, 2026)
- City of Seattle, 2018 Seattle Residential Code, Chapter 3, Building Planning (current version)
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