Room Area Calculator

Calculate RERA Net Carpet Area, Built-Up Plinth Area, and Super Built-Up Saleable Area across multi-room apartment layouts. Computes property cost, usable carpet efficiency %, stamp duty, and interior fit-out budgets.

⚡ Interactive Calculation Engine Active

Please enable JavaScript in your browser to run live computations, 2D envelope diagrams, and export PDF reports.

How to Use Room Area Calculator

  1. Select your unit system: Feet (ft) or Meters (m).
  2. Choose a standard floor plan preset (1 BHK, 2 BHK, 3 BHK, 4 BHK, Villa) or click 'Add Room' to build a custom room layout.
  3. Assign each room its appropriate architectural classification: Living/Bed/Kitchen (Carpet), Bathroom/Toilet (Carpet), Balcony/Terrace (Built-up), Dry Utility (Built-up), or Passage/Foyer (Carpet).
  4. Enter the length and width dimensions for each room.
  5. Specify external wall thickness (4.5", 6", 9", or 11") and builder Common Loading Factor (typically 25% to 35%).
  6. Enter prevailing property rate per sq ft, interior fit-out rate, and stamp duty percentage.
  7. Inspect the live 2D Layout Schematic Plan and review the RERA Net Carpet, Plinth Built-Up, and Super Built-Up breakdown.
  8. Click 'Copy' or 'PDF Report' to export a formatted architectural area certificate.

Architectural Formula Guide: RERA Area Standards & NBC 2016

When auditing real estate floor plans: • **RERA Net Carpet:** $\sum (\text{Length} \times \text{Width})_\text{Habitable} + \sum (\text{Length} \times \text{Width})_\text{Toilets} + \text{Internal Partitions}$ • **Wall Area Factor:** $(\text{Perimeter} / 2) \times \text{Wall Thickness}$ • **Built-Up Area:** $\text{Carpet Area} + \text{Balconies} + \text{Utilities} + \text{Wall Area}$ • **Super Built-Up Area:** $\text{Built-Up Area} \times (1 + \text{Loading \%})$ • **Space Efficiency Index:** $(\text{Carpet Area} / \text{Super Built-Up Area}) \times 100$

Turnkey Interior Fit-out Budgeting Benchmarks

Interior fit-out budgets are always calculated on the Net Usable Carpet Area: • **Essential / Rental Fit-Out (₹800 - ₹1,000/sq ft):** Basic modular kitchen, laminate wardrobes in bedrooms, basic LED electricals, and paint. • **Premium Residential Fit-Out (₹1,300 - ₹1,800/sq ft):** Acrylic/PU modular kitchen, sliding wardrobes with lofts, false ceilings with cove lights, and wallpaper/texture accents. • **Luxury Architectural Fit-Out (₹2,200 - ₹3,500/sq ft):** Veneer/Duco carpentry, Italian marble flooring, automated smart home lighting, designer bathrooms, and custom acoustic paneling.

Frequently Asked Questions

What is the exact definition of RERA Carpet Area in India?
Under the Real Estate (Regulation and Development) Act (RERA) 2016, 'Carpet Area' is defined as the net usable floor area of an apartment, excluding external walls, service shafts, private balconies, and exclusive open terraces, but INCLUDING internal partition walls. Builders in India are legally mandated to quote property prices based on RERA Carpet Area rather than ambiguous Super Built-Up areas.
What is the difference between Carpet Area, Built-Up Area, and Super Built-Up Area?
• Carpet Area: Usable floor space where you can spread a carpet (Bedrooms + Living + Kitchen + Bathrooms + Internal Walls). • Built-Up Area (Plinth Area): Carpet Area + External Wall Thickness (9") + Attached Balconies & Verandahs (typically 10% to 15% larger than carpet area). • Super Built-Up Area (Saleable Area): Built-Up Area + Proportionate share of common building amenities (Lobbies, Lift Wells, Staircases, Clubhouse, Corridors, Security Room) via the loading factor (typically 25% to 35% larger than built-up area).
What is the Builder Loading Factor and how is it calculated?
Loading factor represents the percentage markup added by developers to the built-up area to account for shared common spaces. Formula: Super Built-up Area = Built-up Area × (1 + Loading%/100). For example, if a 2 BHK has a built-up area of 800 sq ft and loading is 30%, the Super Built-Up Area is 800 × 1.30 = 1,040 sq ft.
What is Carpet Space Efficiency and what is considered a healthy ratio?
Carpet Space Efficiency is the ratio of Net Usable Carpet Area to Super Built-Up Area: Efficiency % = (Carpet Area / Super Built-Up Area) × 100. In high-rise residential towers: • 70% to 75% is considered Excellent efficiency. • 65% to 70% is Normal/Average. • Below 60% indicates excessive common loading and wasted saleable cost.
Why does Effective Carpet Rate differ from the Builder Quoted Rate?
Builders quote property prices on Super Built-Up Area (e.g., ₹6,000/sq ft on 1,000 sq ft Super = ₹60 Lakhs). However, if the actual usable carpet area is only 700 sq ft, the true Effective Carpet Rate paid per usable square foot is ₹60 Lakhs / 700 sq ft = ₹8,571/sq ft.
Are private balconies and utility areas included in RERA Carpet Area?
No. Under RERA guidelines, external open balconies, verandahs, dry utility wash yards, and private open terraces are strictly excluded from the Carpet Area calculation and must be disclosed separately under Built-Up / Balcony area in official builder agreement floor plans.