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Window Replacement Calculator
Estimate window replacement cost, total glass area, and material quantities for your home window replacement project. Enter window count, size, and type for an instant rough estimate.
About This Calculator
Enter the number of windows, their typical size (width × height in inches), and window type to get an instant rough estimate of total glass area and installed replacement cost. Typical cost estimates are national mid-range averages — enter your own contractor quote to get a project-specific total.
How It Works
Window area = (widthIn × heightIn) ÷ 144 (sq ft per window). Total area = windowCount × windowArea. Estimated cost per window is sourced from national mid-range installed averages (HomeAdvisor / Angi 2024–2025) and can be overridden with your own contractor quote. Total cost = count × cost per window.
The Formula
totalCost = windowCount × costPerWindow
- windowCount
- number of windows to replace
- costPerWindow
- installed cost per window (USD) — mid-range estimate or your quote
Frequently Asked Questions
- How accurate are the typical cost estimates?
- The per-window typical costs are national mid-range installed averages from HomeAdvisor / Angi (2024–2025). Actual costs vary significantly by region, window brand, glass type (single/double/triple pane, low-E coating), frame material (vinyl, wood, fiberglass), and labor market. These figures are rough order-of-magnitude guidance only — always obtain at least three contractor quotes before committing.
- What does "installed cost" include?
- Installed cost typically covers the window unit itself (frame + glass), removal and disposal of the old window, installation labor, and basic interior/exterior trim. It generally does not include significant structural work, reframing, interior painting, or custom trim upgrades. Confirm scope with your contractor.
- Should I measure rough opening or window unit size?
- For this calculator, enter the window unit size (frame width × frame height), not the rough opening (which is slightly larger). Alternatively, measure the visible glass area if that is the dimension you know — the area calculation gives the same glass coverage either way.
- What is a double hung window?
- A double hung window has two sashes (upper and lower) that both slide vertically. It is the most common residential window type in the United States, typically running $400–$800 installed for standard sizes. Casement windows (crank-operated, swinging outward) tend to run slightly higher; bay windows significantly higher due to structural framing.
Estimates only. Coverage figures (sq ft/gallon, bag yield, BTU/sq ft) are industry rules of thumb with real-world variance. Verify quantities with your supplier before purchasing.