What's a typical window-to-wall ratio?

Residential buildings commonly range from 15-25% WWR, while commercial buildings — especially glass-heavy office towers — can range much higher, sometimes 40-60% or more.

Why does WWR matter for energy codes?

Higher WWR generally increases heating and cooling loads (more glass means more heat gain/loss), so many energy codes cap WWR or require better-performing glazing above certain thresholds.

Window-to-Wall Ratio Calculator

Calculate the window-to-wall ratio (WWR) — the percentage of exterior wall area occupied by windows — a key metric in building energy modeling, daylighting design, and code compliance checks.

Inputs

Results

Window-to-Wall Ratio: 12.5%

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Formula

WWR = (Total Window Area / Total Wall Area) × 100

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Exterior Finishing Estimates: Insulation, Windows, Stucco, and Paint

How to estimate insulation batts, window-to-wall ratio, stucco coverage, and paint gallons for finishing a building's exterior.

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