Calculate room floor area, total window area, openable area, ventilation ratio and a practical ventilation score for bedrooms, kitchens, bathrooms and living spaces.
Enter the room and window details below.
The final score is a practical guidance score built from window-to-floor ratio, openable area, room type, cross ventilation and occupant load. It is not a substitute for local building regulations or professional design.
There is no single percentage that is correct for every room, climate or local authority. For a quick design check, this calculator uses practical target bands that vary by room type.
| Room Type | Practical Window Area Target | Openable Area Target |
|---|---|---|
| Bedroom | About 15% of floor area | About 7.5% |
| Living Room | About 15% | About 7.5% |
| Kitchen | About 20% | About 10% |
| Bathroom / Toilet | About 10% | About 5% |
| Study / Office | About 15% | About 7.5% |
These are calculator guidance values, not legal minimums. Always check the applicable building bye-laws, development authority rules and project drawings.
Cross ventilation works best when air can enter from one opening and leave through another opening on an opposite or adjacent wall. This generally improves air movement compared with having all windows on only one wall.
Room layout, external obstructions, wind direction, window height, grills, curtains and furniture can all affect real airflow.
A practical target depends on room type, local rules and climate. This tool compares your window area with simple room-specific target bands for preliminary planning.
It is the part of the window that can actually open and allow air to pass. A large fixed-glass window may provide daylight but little natural ventilation.
Cross ventilation occurs when air enters through one opening and exits through another opening on a different wall, creating a more effective airflow path.
Yes. Select Kitchen from the room type list. The calculator uses a higher practical target for kitchens because ventilation needs are generally greater.
No. It is a preliminary planning and educational tool. Actual design should follow local bye-laws, site conditions and professional design requirements.
VentCalc India provides approximate planning guidance only. The score and target percentages used by this tool are not a legal compliance check. Building regulations vary by location and project type. Always verify the applicable local bye-laws and consult a qualified architect or engineer for final design.