Window Size Calculator
Enter your room size, its use and how much daylight you want. Get the right window size, the glazing area and the openable area — tuned to the NBC ~10 per cent daylight rule. Indicative India 2026; always verify your local building bye-law.
Your room
Floor area is 120 sq ft. We size glazing to 13% of the floor (Brighter, everyday-pleasant rooms.) and assume openable ≈ half the glazing for ventilation, following NBC practice. Confirm exact ratios in your local bye-law.
Recommended window size
0.0 × 0.0 ft
1 window · about 15 sq ft glazed each
Required glazing
15 sq ft
13% of floor
Openable area
7.5 sq ft
≈ half, for airflow
Glazing / window
15 sq ft
Sill height
600–750 mm
low sill, headboard clearance
Your recommended glazing vs a typical ~10% Indian room. Indicative — verify local bye-law.
Place windows that flood your rooms with light
DesignAI sizes and positions windows for daylight, ventilation and views — to your room, orientation and climate.
Related Guides — Deep-dive reading
National Building Code Window Requirements
What NBC 2016 requires of a home window in India: glazed area for light, openable area for ventilation, by-room minimums, ceiling heights and the bye-law that actually governs.
Windows & GlazingNorth-Facing Window Design (India): The Best Light With the Least Heat
Why the north wall gives soft, even, glare-free daylight with almost no heat, and how to design large, high-VLT windows that make the most of it.
Windows & GlazingWindow Design for Cross Ventilation (India): Inlet, Outlet and the Path of the Breeze
How to size, place and choose windows so a breeze actually crosses the room, windward inlet to leeward outlet, with the right window types and a clear flow path.
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