United-inches sizing convention (common window sizes)

Typical published planning values / code minimums — NOT a certified design or a compliance sign-off. Actual egress compliance and energy performance depend on your local building code (AHJ), climate zone, the exact product’s NFRC-rated U-factor & SHGC and the installation; confirm against local code and the manufacturer’s NFRC label, and consult a pro. Structural headers for enlarged openings, whole-building heat-load / HVAC sizing and code certification are set by code and a professional — not engineered here.

Suppliers order and price windows by united inches (UI) = width + height. This table tabulates UI and glass square footage (width × height ÷ 144) for common stock sizes — a labeled planning convention, confirm availability with the supplier. Use it with the united-inches calculator and the standard vs custom size reference.

Nominal size (W × H)United inchesGlass area
24 × 36 in60 UI6.0 sq ft
24 × 48 in72 UI8.0 sq ft
28 × 54 in82 UI10.5 sq ft
30 × 36 in66 UI7.5 sq ft
30 × 48 in78 UI10.0 sq ft
30 × 60 in90 UI12.5 sq ft
32 × 48 in80 UI10.7 sq ft
32 × 54 in86 UI12.0 sq ft
36 × 48 in84 UI12.0 sq ft
36 × 54 in90 UI13.5 sq ft
36 × 60 in96 UI15.0 sq ft
36 × 72 in108 UI18.0 sq ft
48 × 48 in96 UI16.0 sq ft
48 × 60 in108 UI20.0 sq ft
60 × 48 in108 UI20.0 sq ft
72 × 60 in132 UI30.0 sq ft

LABELED common stock sizes — united inches = width + height; glass area = width × height ÷ 144. A planning convention; confirm availability and exact sizes with the supplier, and measure your own openings before ordering.

Related calculators

United-inches calculatorWork out a window's united inches (width + height) — the number suppliers use to size and price windows. Formula, a worked example and a common-size chart.Window area (square footage)Convert window width and height (inches) to glass area in square feet: width × height ÷ 144. Worked example, a size chart and the frame-vs-daylight difference.Standard vs custom sizeCheck whether a window size is common stock or custom: a labeled stock-size chart, why replacements are usually custom, and the cost and lead-time impact.